diff --git a/appDodge/Main.hs b/appDodge/Main.hs
index 083eac5fe..472db59ac 100644
--- a/appDodge/Main.hs
+++ b/appDodge/Main.hs
@@ -26,7 +26,7 @@ import Control.Lens
 import Control.Monad
 --import Control.Monad.Parallel
 import qualified Data.Text as T
-import qualified Data.IntMap               as IM
+import qualified IntMapHelp               as IM
 import Graphics.Rendering.OpenGL hiding (color, rotate, scale, translate)
 import qualified SDL
 import qualified SDL.Mixer                 as Mix
diff --git a/package.yaml b/package.yaml
index 7f62b581a..e99c68c08 100644
--- a/package.yaml
+++ b/package.yaml
@@ -22,6 +22,8 @@ description:         Description text, TODO link to README.md
 dependencies:
 - base >= 4.7 && < 5
 - containers
+- strict-containers
+- strict-containers-lens
 - unordered-containers
 - bitwise-enum
 - graphviz
diff --git a/src/Dodge/Base/Collide.hs b/src/Dodge/Base/Collide.hs
index 471dd2ee2..60e57a31c 100644
--- a/src/Dodge/Base/Collide.hs
+++ b/src/Dodge/Base/Collide.hs
@@ -44,7 +44,7 @@ import Dodge.Base.Wall
 import Geometry
 
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 import Control.Monad
 import StreamingHelp
diff --git a/src/Dodge/Base/Item.hs b/src/Dodge/Base/Item.hs
index c9c6a3fc1..819d726f8 100644
--- a/src/Dodge/Base/Item.hs
+++ b/src/Dodge/Base/Item.hs
@@ -5,7 +5,7 @@ module Dodge.Base.Item
 --import Dodge.Base.You
 --import LensHelp
 --
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 --selectedObject :: World -> Maybe (Either FloorItem Button)
 --selectedObject w = lookup (_crInvSel ycr) $ zip [n..] $ _closeObjects w
diff --git a/src/Dodge/Beam.hs b/src/Dodge/Beam.hs
index fd36b1d5c..76743c998 100644
--- a/src/Dodge/Beam.hs
+++ b/src/Dodge/Beam.hs
@@ -17,7 +17,7 @@ import Picture
 --import Data.List (sortOn)
 --import MonadHelp
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 doBeamCombine :: BeamCombineType 
     -> (Point2,(Point2,Point2,Beam),(Point2,Point2,Beam))
diff --git a/src/Dodge/Block.hs b/src/Dodge/Block.hs
index 8249f8e32..a15416064 100644
--- a/src/Dodge/Block.hs
+++ b/src/Dodge/Block.hs
@@ -17,7 +17,7 @@ import Data.Foldable
 import Data.Function
 import Data.Maybe
 import qualified Data.IntSet as IS
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 import qualified Streaming.Prelude as S
 import qualified Data.Graph.Inductive as FGL
diff --git a/src/Dodge/Bullet.hs b/src/Dodge/Bullet.hs
index 559eab616..470828106 100644
--- a/src/Dodge/Bullet.hs
+++ b/src/Dodge/Bullet.hs
@@ -12,7 +12,7 @@ import Geometry
 import LensHelp
 import StreamingHelp
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Streaming.Prelude as S
 import Data.Maybe
 import Dodge.Movement.Turn
diff --git a/src/Dodge/Combine.hs b/src/Dodge/Combine.hs
index 6885b63ff..e8413a555 100644
--- a/src/Dodge/Combine.hs
+++ b/src/Dodge/Combine.hs
@@ -22,7 +22,7 @@ import Data.Map.Merge.Strict
 import Control.Monad
 import Control.Lens
 import Data.Bifunctor
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 --import qualified Data.IntSet as IS
 import qualified Data.Map.Strict as M
 --import Data.Map.Merge.Strict
diff --git a/src/Dodge/Creature.hs.orig b/src/Dodge/Creature.hs.orig
index 0ca65ad42..01bf918aa 100644
--- a/src/Dodge/Creature.hs.orig
+++ b/src/Dodge/Creature.hs.orig
@@ -32,7 +32,7 @@ import Control.Monad.State
 import Control.Monad
 import System.Random
 import qualified Data.Set as S
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map as M
 import Foreign.ForeignPtr
 import Control.Concurrent
diff --git a/src/Dodge/Creature/ArmourChase.hs b/src/Dodge/Creature/ArmourChase.hs
index c2804e722..e024db390 100644
--- a/src/Dodge/Creature/ArmourChase.hs
+++ b/src/Dodge/Creature/ArmourChase.hs
@@ -8,7 +8,7 @@ import Dodge.Creature.ChaseCrit
 import Dodge.Item.Equipment
 import Dodge.Item.Consumable
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 flockArmourChaseCrit :: Creature
diff --git a/src/Dodge/Creature/AutoCrit.hs b/src/Dodge/Creature/AutoCrit.hs
index e1f576c62..45567530d 100644
--- a/src/Dodge/Creature/AutoCrit.hs
+++ b/src/Dodge/Creature/AutoCrit.hs
@@ -7,7 +7,7 @@ import Dodge.Item.Weapon.BulletGuns
 import Dodge.Item.Consumable
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 autoCrit :: Creature
diff --git a/src/Dodge/Creature/Boid.hs b/src/Dodge/Creature/Boid.hs
index 7b24261e3..973a0b1b6 100644
--- a/src/Dodge/Creature/Boid.hs
+++ b/src/Dodge/Creature/Boid.hs
@@ -7,7 +7,7 @@ import Geometry
 
 import Control.Monad.Reader
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 interpWith :: Float -> Point2 -> Point2 -> Point2
 interpWith x a b = x *.* a +.+ (1 - x) *.* b
diff --git a/src/Dodge/Creature/ChaseCrit.hs b/src/Dodge/Creature/ChaseCrit.hs
index 8ebc07e84..7732cc0d9 100644
--- a/src/Dodge/Creature/ChaseCrit.hs
+++ b/src/Dodge/Creature/ChaseCrit.hs
@@ -11,7 +11,7 @@ import Dodge.Item.Equipment
 import Dodge.SoundLogic
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 --import System.Random
 
diff --git a/src/Dodge/Creature/ChooseTarget.hs b/src/Dodge/Creature/ChooseTarget.hs
index 24e9129de..212f20344 100644
--- a/src/Dodge/Creature/ChooseTarget.hs
+++ b/src/Dodge/Creature/ChooseTarget.hs
@@ -4,7 +4,7 @@ import Dodge.Data
 import Dodge.Base
 
 import Control.Lens
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 targetYouLOS :: Creature -> World -> Maybe Creature
 {-# INLINE targetYouLOS #-}
diff --git a/src/Dodge/Creature/Impulse.hs b/src/Dodge/Creature/Impulse.hs
index c60e7e113..45285e09a 100644
--- a/src/Dodge/Creature/Impulse.hs
+++ b/src/Dodge/Creature/Impulse.hs
@@ -11,7 +11,7 @@ import Dodge.SoundLogic
 import Geometry
 import LensHelp
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import System.Random
 import Control.Monad.State
 import Data.Bifunctor
diff --git a/src/Dodge/Creature/Impulse/Movement.hs b/src/Dodge/Creature/Impulse/Movement.hs
index 1dffe5686..694adabdf 100644
--- a/src/Dodge/Creature/Impulse/Movement.hs
+++ b/src/Dodge/Creature/Impulse/Movement.hs
@@ -4,7 +4,7 @@ import Dodge.Creature.Statistics
 import Geometry
 
 --import Data.Maybe
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 import Control.Lens
 {- | Creature attempts to moves under its own steam.
 The idea is that this may or may not work, depending on the status of the creature. 
diff --git a/src/Dodge/Creature/Impulse/UseItem.hs b/src/Dodge/Creature/Impulse/UseItem.hs
index 7e15b4b2b..ecce3500e 100644
--- a/src/Dodge/Creature/Impulse/UseItem.hs
+++ b/src/Dodge/Creature/Impulse/UseItem.hs
@@ -11,7 +11,7 @@ import Dodge.Reloading
 import Dodge.Item.Location
 import Dodge.HeldUse
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 import qualified SDL
 --import qualified Data.IntSet as IS
diff --git a/src/Dodge/Creature/LauncherCrit.hs b/src/Dodge/Creature/LauncherCrit.hs
index c4d35df44..23bc2d5cb 100644
--- a/src/Dodge/Creature/LauncherCrit.hs
+++ b/src/Dodge/Creature/LauncherCrit.hs
@@ -7,7 +7,7 @@ import Dodge.Default
 import Dodge.Item.Weapon.Launcher
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 launcherCrit :: Creature
diff --git a/src/Dodge/Creature/LtAutoCrit.hs b/src/Dodge/Creature/LtAutoCrit.hs
index 36375ff47..995fe71a9 100644
--- a/src/Dodge/Creature/LtAutoCrit.hs
+++ b/src/Dodge/Creature/LtAutoCrit.hs
@@ -7,7 +7,7 @@ import Dodge.Item.Weapon.BulletGuns
 import Dodge.Item.Consumable
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 ltAutoCrit :: Creature
diff --git a/src/Dodge/Creature/Perception.hs b/src/Dodge/Creature/Perception.hs
index 839089880..6e91dac4c 100644
--- a/src/Dodge/Creature/Perception.hs
+++ b/src/Dodge/Creature/Perception.hs
@@ -17,7 +17,7 @@ import Sound.Data
 
 import Data.Maybe
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 
 perceptionUpdate
@@ -35,7 +35,7 @@ chaseCritPerceptionUpdate is w =
  of attention -} -- TODO delete?
 basicAwarenessUpdate :: Creature -> Creature
 basicAwarenessUpdate cr = case _cpAttention $ _crPerception cr of
-    Fixated i -> cr & crPerception . cpAwareness 
+    Fixated i -> cr & crPerception . cpAwareness
         %~ (IM.insert i (Cognizant 10000) . IM.mapMaybe decreaseAwareness)
     AttentiveTo is -> cr 
         & crPerception . cpAwareness 
diff --git a/src/Dodge/Creature/Perception/Data.hs b/src/Dodge/Creature/Perception/Data.hs
index ce227fe14..fbdc65881 100644
--- a/src/Dodge/Creature/Perception/Data.hs
+++ b/src/Dodge/Creature/Perception/Data.hs
@@ -21,7 +21,7 @@ module Dodge.Creature.Perception.Data
     )
     where
 import Control.Lens
-import qualified Data.IntMap as IM
+import qualified IntMapHelp as IM
 
 data Perception = Perception
     { _cpVigilance     :: Vigilance
diff --git a/src/Dodge/Creature/PistolCrit.hs b/src/Dodge/Creature/PistolCrit.hs
index b28c7cc22..c752183b3 100644
--- a/src/Dodge/Creature/PistolCrit.hs
+++ b/src/Dodge/Creature/PistolCrit.hs
@@ -7,7 +7,7 @@ import Dodge.Item.Weapon.BulletGuns
 import Dodge.Item.Consumable
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 pistolCrit :: Creature
diff --git a/src/Dodge/Creature/ReaderUpdate.hs b/src/Dodge/Creature/ReaderUpdate.hs
index 176804ef6..aac3d4234 100644
--- a/src/Dodge/Creature/ReaderUpdate.hs
+++ b/src/Dodge/Creature/ReaderUpdate.hs
@@ -22,7 +22,7 @@ import Dodge.Zone
 import Dodge.Path
 import Geometry
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 import Control.Applicative
 import Data.Maybe
diff --git a/src/Dodge/Creature/SetTarget.hs b/src/Dodge/Creature/SetTarget.hs
index f93141bbd..4f484da80 100644
--- a/src/Dodge/Creature/SetTarget.hs
+++ b/src/Dodge/Creature/SetTarget.hs
@@ -3,7 +3,7 @@ module Dodge.Creature.SetTarget where
 import Dodge.Data
 
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 {- | Assumes that you are id 0: if creature is cognizant of you, sets you as target -}
 targetYouWhenCognizant
     :: World
diff --git a/src/Dodge/Creature/SpreadGunCrit.hs b/src/Dodge/Creature/SpreadGunCrit.hs
index 319019b58..0cf0479d0 100644
--- a/src/Dodge/Creature/SpreadGunCrit.hs
+++ b/src/Dodge/Creature/SpreadGunCrit.hs
@@ -7,7 +7,7 @@ import Dodge.Item.Weapon.BulletGuns
 import Dodge.Item.Consumable
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 spreadGunCrit :: Creature
diff --git a/src/Dodge/Creature/Statistics.hs b/src/Dodge/Creature/Statistics.hs
index 35c0e4a14..6f77c5e26 100644
--- a/src/Dodge/Creature/Statistics.hs
+++ b/src/Dodge/Creature/Statistics.hs
@@ -8,7 +8,7 @@ import qualified IntMapHelp as IM
 import LensHelp
 
 import Data.Maybe
-import Data.IntMap.Merge.Strict
+import Data.Strict.IntMap.Autogen.Merge.Strict
 
 getCrDexterity :: Creature -> Int
 getCrDexterity cr = _dexterity (_crStatistics cr)
@@ -26,7 +26,7 @@ equipmentStrValue itm = case _iyBase $ _itType itm of
     _ -> 0
 
 crCurrentEquipment :: Creature -> IM.IntMap Item
-crCurrentEquipment cr =  merge dropMissing dropMissing (zipWithMatched (\_ _ itm -> itm))
+crCurrentEquipment cr = merge dropMissing dropMissing (zipWithMatched (\_ _ itm -> itm))
     (_crInvEquipped cr)
     (_crInv cr)
 
diff --git a/src/Dodge/Creature/Test.hs b/src/Dodge/Creature/Test.hs
index 7fc0ff833..e2fe7ee97 100644
--- a/src/Dodge/Creature/Test.hs
+++ b/src/Dodge/Creature/Test.hs
@@ -31,7 +31,7 @@ import SameConstr
 
 import Data.List (find)
 import Data.Maybe
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 import Control.Lens
 
 crIsReloading :: Creature -> Bool
diff --git a/src/Dodge/Data.hs b/src/Dodge/Data.hs
index 6e2f8b8fb..db4d40ed0 100644
--- a/src/Dodge/Data.hs
+++ b/src/Dodge/Data.hs
@@ -147,7 +147,7 @@ import System.Random
 import Data.Graph.Inductive
 import qualified Data.Set as S
 import qualified Data.IntSet as IS
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 import qualified Data.Text as T
 import SDL (Scancode, MouseButton)
diff --git a/src/Dodge/Data.hs.orig b/src/Dodge/Data.hs.orig
index 920530a6f..1d8e2f848 100644
--- a/src/Dodge/Data.hs.orig
+++ b/src/Dodge/Data.hs.orig
@@ -16,7 +16,7 @@ import Control.Monad.State
 import System.Random
 import Data.Graph.Inductive
 import qualified Data.Set as S
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map as M
 import qualified SDL.Mixer as Mix
 import SDL (Scancode, MouseButton)
diff --git a/src/Dodge/Data/Item.hs b/src/Dodge/Data/Item.hs
index 307ec41cb..a2c9e3a6e 100644
--- a/src/Dodge/Data/Item.hs
+++ b/src/Dodge/Data/Item.hs
@@ -4,7 +4,6 @@ module Dodge.Data.Item
     ( module Dodge.Data.Item
     , module Dodge.Data.Item.Misc
     ) where
-import Geometry.Data
 import Control.Lens
 import Dodge.Data.Item.Misc
 import Dodge.Data.Item.Consumption
@@ -17,7 +16,7 @@ import Dodge.Combine.Data
 import Dodge.Item.Attachment.Data
 import Color
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 data Item = Item
     { _itConsumption    :: ItemConsumption
     , _itUse        :: ItemUse
diff --git a/src/Dodge/Data/Zoning.hs b/src/Dodge/Data/Zoning.hs
index dc1e8f0c8..e9853943c 100644
--- a/src/Dodge/Data/Zoning.hs
+++ b/src/Dodge/Data/Zoning.hs
@@ -3,7 +3,7 @@
 module Dodge.Data.Zoning where
 import Geometry.Data
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import StreamingHelp
 
 data Zoning t a = Zoning
diff --git a/src/Dodge/Default/Creature.hs b/src/Dodge/Default/Creature.hs
index fc5ceb7bf..8eed284e7 100644
--- a/src/Dodge/Default/Creature.hs
+++ b/src/Dodge/Default/Creature.hs
@@ -4,7 +4,7 @@ import Dodge.Creature.Picture
 import Geometry.Data
 import Picture
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 
 import Control.Lens
@@ -71,8 +71,8 @@ defaultInvSize = 20
 defaultPerceptionState :: Perception
 defaultPerceptionState = Perception
     { _cpVigilance      = Lethargic
-    , _cpAttention      = AttentiveTo IM.empty
-    , _cpAwareness      = IM.empty
+    , _cpAttention      = AttentiveTo mempty
+    , _cpAwareness      = mempty
     , _cpVision         = defaultVision
     , _cpAudition       = defaultAudition
     }
diff --git a/src/Dodge/Default/Room.hs b/src/Dodge/Default/Room.hs
index ddace4e4d..d07eb10d7 100644
--- a/src/Dodge/Default/Room.hs
+++ b/src/Dodge/Default/Room.hs
@@ -3,7 +3,7 @@ import Data.Tile
 import Geometry.Data
 --import Dodge.LevelGen.Data
 import Dodge.Data
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Set as S
 
 defaultRoom :: Room
diff --git a/src/Dodge/Default/World.hs b/src/Dodge/Default/World.hs
index c052a8309..5baf5ab3d 100644
--- a/src/Dodge/Default/World.hs
+++ b/src/Dodge/Default/World.hs
@@ -12,7 +12,7 @@ import Geometry.Data
 import Geometry.Polygon
 
 import System.Random
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map as M
 import qualified Data.Set as S
 import Data.Graph.Inductive.Graph hiding ((&))
diff --git a/src/Dodge/Default/World.hs.orig b/src/Dodge/Default/World.hs.orig
index 651cf4275..865a0bffc 100644
--- a/src/Dodge/Default/World.hs.orig
+++ b/src/Dodge/Default/World.hs.orig
@@ -15,7 +15,7 @@ import Geometry.Polygon
 
 import Control.Lens
 import System.Random
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map as M
 import qualified Data.Set as S
 import Data.Graph.Inductive.Graph hiding ((&))
diff --git a/src/Dodge/Equipment.hs b/src/Dodge/Equipment.hs
index 0df236357..3580a1a53 100644
--- a/src/Dodge/Equipment.hs
+++ b/src/Dodge/Equipment.hs
@@ -1,8 +1,8 @@
 module Dodge.Equipment where
 import Dodge.Data
 
-import qualified Data.IntMap.Strict as IM
-import Data.IntMap.Merge.Strict
+import qualified IntMapHelp as IM
+import Data.Strict.IntMap.Autogen.Merge.Strict
 
 getCrEquipment :: Creature -> IM.IntMap Item
 getCrEquipment cr = merge dropMissing dropMissing (zipWithMatched $ \_ _ -> id)
diff --git a/src/Dodge/Event/Keyboard.hs b/src/Dodge/Event/Keyboard.hs
index 497cf1081..64009a481 100644
--- a/src/Dodge/Event/Keyboard.hs
+++ b/src/Dodge/Event/Keyboard.hs
@@ -20,7 +20,7 @@ import LensHelp
 --import Color
 
 --import Data.List
-import qualified Data.IntMap.Strict    as IM
+import qualified IntMapHelp    as IM
 import           Data.Maybe
 import qualified Data.Set              as S
 import           SDL
diff --git a/src/Dodge/Event/Test.hs b/src/Dodge/Event/Test.hs
index 0d99baa22..f2113339b 100644
--- a/src/Dodge/Event/Test.hs
+++ b/src/Dodge/Event/Test.hs
@@ -8,7 +8,7 @@ import Dodge.Data
 --import Picture
 --import Geometry
 --
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 --import Control.Lens
 testEvent :: World -> World
 testEvent w = w
diff --git a/src/Dodge/Floor.hs b/src/Dodge/Floor.hs
index b3f62917e..62e73d901 100644
--- a/src/Dodge/Floor.hs
+++ b/src/Dodge/Floor.hs
@@ -35,7 +35,7 @@ import RandomHelp
 import Data.List (intersperse)
 --import Data.Sequence hiding (zipWith)
 --import Data.Maybe
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 initialAnoTree :: Annotation
 initialAnoTree = OnwardList 
diff --git a/src/Dodge/Initialisation.hs b/src/Dodge/Initialisation.hs
index 9f2026838..21fca39d1 100644
--- a/src/Dodge/Initialisation.hs
+++ b/src/Dodge/Initialisation.hs
@@ -13,7 +13,7 @@ import Geometry.Data
 
 import System.Random
 import qualified Data.Set as S
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map as M
 
 initialWorld :: World
diff --git a/src/Dodge/Inventory/Add.hs b/src/Dodge/Inventory/Add.hs
index 0d162a814..6b91e361b 100644
--- a/src/Dodge/Inventory/Add.hs
+++ b/src/Dodge/Inventory/Add.hs
@@ -7,7 +7,7 @@ import Dodge.Base.You
 
 import Data.Maybe
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 putItemInInvID :: Int -> Int -> World -> (Maybe Int,World)
 putItemInInvID cid flid w = fromMaybe (Nothing,w) $ do
diff --git a/src/Dodge/Item/Attachment.hs b/src/Dodge/Item/Attachment.hs
index 57dfd7626..5fe484ba6 100644
--- a/src/Dodge/Item/Attachment.hs
+++ b/src/Dodge/Item/Attachment.hs
@@ -9,7 +9,7 @@ import Dodge.Default
 import Control.Lens hiding ((|>),(<|))
 import Data.Sequence
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 
 charFiringStratI
diff --git a/src/Dodge/Item/Consumable.hs b/src/Dodge/Item/Consumable.hs
index 9d88a78cf..a67701b16 100644
--- a/src/Dodge/Item/Consumable.hs
+++ b/src/Dodge/Item/Consumable.hs
@@ -10,7 +10,7 @@ import Dodge.SoundLogic
 
 --import Data.Maybe
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 medkit :: Int -> Item
 medkit i = defaultConsumable
diff --git a/src/Dodge/Item/Draw.hs b/src/Dodge/Item/Draw.hs
index d2803ea85..7fa1a7a56 100644
--- a/src/Dodge/Item/Draw.hs
+++ b/src/Dodge/Item/Draw.hs
@@ -12,7 +12,7 @@ import ShapePicture
 import Dodge.Item.Equipment.Shape
 import Dodge.Item.Draw.SPic
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 itemEquipPict :: Creature -> Item -> SPic
diff --git a/src/Dodge/Item/Weapon/BatteryGuns.hs b/src/Dodge/Item/Weapon/BatteryGuns.hs
index c3337132d..a616f10cf 100644
--- a/src/Dodge/Item/Weapon/BatteryGuns.hs
+++ b/src/Dodge/Item/Weapon/BatteryGuns.hs
@@ -38,7 +38,7 @@ import LensHelp
 --import Data.List (sortOn)
 --import System.Random
 --import Data.Tuple
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 --import Control.Monad.State
 
diff --git a/src/Dodge/Item/Weapon/Remote.hs b/src/Dodge/Item/Weapon/Remote.hs
index 9c4e0beea..71c959933 100644
--- a/src/Dodge/Item/Weapon/Remote.hs
+++ b/src/Dodge/Item/Weapon/Remote.hs
@@ -8,7 +8,7 @@ import Dodge.Default
 import Geometry
 import Dodge.Item.Location
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 
 setRemoteBombScope :: Int -> Prop -> World -> World
diff --git a/src/Dodge/Item/Weapon/SonicGuns.hs b/src/Dodge/Item/Weapon/SonicGuns.hs
index e47d3d338..e40a0e4ee 100644
--- a/src/Dodge/Item/Weapon/SonicGuns.hs
+++ b/src/Dodge/Item/Weapon/SonicGuns.hs
@@ -16,7 +16,7 @@ import LensHelp
 --import Data.Bifunctor
 --import System.Random
 --import Data.Tuple
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 sonicGun :: Item
 sonicGun = defaultAutoGun 
diff --git a/src/Dodge/Item/Weapon/Targeting.hs b/src/Dodge/Item/Weapon/Targeting.hs
index 6493907d1..5c0b04534 100644
--- a/src/Dodge/Item/Weapon/Targeting.hs
+++ b/src/Dodge/Item/Weapon/Targeting.hs
@@ -6,7 +6,7 @@ import Dodge.Data
 import Geometry.Data
 
 import Control.Lens
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 useTargetPos 
     :: (Maybe Point2 -> Creature -> World -> World)
     -> Creature
diff --git a/src/Dodge/Item/Weapon/TriggerType.hs b/src/Dodge/Item/Weapon/TriggerType.hs
index 396b3e5ad..04d7569fc 100644
--- a/src/Dodge/Item/Weapon/TriggerType.hs
+++ b/src/Dodge/Item/Weapon/TriggerType.hs
@@ -83,7 +83,7 @@ import LensHelp
 
 --import Control.Lens
 import Data.Maybe
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 import Data.Foldable
 
 type ChainEffect 
diff --git a/src/Dodge/Lampoid.hs b/src/Dodge/Lampoid.hs
index bc941a5f6..8e68412a6 100644
--- a/src/Dodge/Lampoid.hs
+++ b/src/Dodge/Lampoid.hs
@@ -11,7 +11,7 @@ import qualified IntMapHelp as IM
 updateLampoid :: Creature -> World -> World
 updateLampoid cr w = case cr ^?! crType . lampLSID of
     Nothing -> let i = IM.newKey (_lightSources w)
-        in w & lightSources . at i ?~ lsColPosID lcol (addZ h cpos) i
+        in w & lightSources %~ IM.insert i (lsColPosID lcol (addZ h cpos) i)
     Just i 
         | _crHP cr < 0 -> w
             & explosionFlashAt cpos 
diff --git a/src/Dodge/LevelGen.hs b/src/Dodge/LevelGen.hs
index d19ef4027..7323f3004 100644
--- a/src/Dodge/LevelGen.hs
+++ b/src/Dodge/LevelGen.hs
@@ -18,7 +18,7 @@ import System.Directory
 import System.Random
 import Control.Lens
 import Control.Monad.State
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Text.IO as TIO
 
 generateWorldFromSeed :: Int -> IO World
diff --git a/src/Dodge/LevelGen/Data.hs b/src/Dodge/LevelGen/Data.hs
index a79039cb6..c0b7f923d 100644
--- a/src/Dodge/LevelGen/Data.hs
+++ b/src/Dodge/LevelGen/Data.hs
@@ -14,7 +14,7 @@ import Control.Lens
 --import Control.Monad.State
 --import System.Random
 import Data.Maybe
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 --import Data.Bifunctor
 
 
diff --git a/src/Dodge/LevelGen/LevelStructure.hs b/src/Dodge/LevelGen/LevelStructure.hs
index c43324092..59dd09e9e 100644
--- a/src/Dodge/LevelGen/LevelStructure.hs
+++ b/src/Dodge/LevelGen/LevelStructure.hs
@@ -12,7 +12,7 @@ import Color
 import LensHelp
 
 --import Data.Tree
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 --import Control.Lens
 
diff --git a/src/Dodge/LevelGen/Switch.hs b/src/Dodge/LevelGen/Switch.hs
index c342b5de5..5bb5742c1 100644
--- a/src/Dodge/LevelGen/Switch.hs
+++ b/src/Dodge/LevelGen/Switch.hs
@@ -12,7 +12,7 @@ import ShapePicture
 import Shape
 import Geometry
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 makeButton 
     :: Color 
diff --git a/src/Dodge/Machine.hs b/src/Dodge/Machine.hs
index 5db2c61bd..7487a69fe 100644
--- a/src/Dodge/Machine.hs
+++ b/src/Dodge/Machine.hs
@@ -8,7 +8,7 @@ import Dodge.SoundLogic
 import Geometry
 import Dodge.Base
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 basicMachineUpdate :: (Machine -> World -> World) -> Machine -> World -> World
 basicMachineUpdate f mc = basicMachineApplyDamage mc . f mc
diff --git a/src/Dodge/Machine/Destroy.hs b/src/Dodge/Machine/Destroy.hs
index 026f6ce79..933ce6c12 100644
--- a/src/Dodge/Machine/Destroy.hs
+++ b/src/Dodge/Machine/Destroy.hs
@@ -5,7 +5,7 @@ import Dodge.WorldEvent.Explosion
 import LensHelp
 
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 destroyMachine :: Machine -> World -> World
 destroyMachine mc = (machines %~ IM.delete (_mcID mc))
diff --git a/src/Dodge/Path.hs b/src/Dodge/Path.hs
index 2130b4581..d3409cd04 100644
--- a/src/Dodge/Path.hs
+++ b/src/Dodge/Path.hs
@@ -21,7 +21,7 @@ import Data.Foldable
 import Control.Lens
 import Data.Maybe
 import Data.List
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 import Data.Graph.Inductive hiding ((&))
 import qualified Data.Set as Set
 import Data.Set (Set)
diff --git a/src/Dodge/Path.hs.orig b/src/Dodge/Path.hs.orig
index 3357d59e8..ecadf0ef6 100644
--- a/src/Dodge/Path.hs.orig
+++ b/src/Dodge/Path.hs.orig
@@ -26,7 +26,7 @@ import Geometry
 import Control.Lens
 import Data.Maybe
 import Data.List
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 import Data.Graph.Inductive hiding ((&))
 import Data.Set (Set)
 import qualified Data.Set as Set
diff --git a/src/Dodge/Placement/Instance/Door.hs b/src/Dodge/Placement/Instance/Door.hs
index 156163f5c..f6ac97e1c 100644
--- a/src/Dodge/Placement/Instance/Door.hs
+++ b/src/Dodge/Placement/Instance/Door.hs
@@ -13,7 +13,7 @@ import Dodge.Creature.Test
 import Dodge.LevelGen.Switch
 
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 putDoubleDoor :: EdgeObstacle -> Wall -> (World -> Bool)  -> Point2 -> Point2 -> Float -> Placement
 putDoubleDoor eo wl cond a b speed 
diff --git a/src/Dodge/Placement/Instance/LightSource/Flicker.hs b/src/Dodge/Placement/Instance/LightSource/Flicker.hs
index 82266648d..04d0c43f9 100644
--- a/src/Dodge/Placement/Instance/LightSource/Flicker.hs
+++ b/src/Dodge/Placement/Instance/LightSource/Flicker.hs
@@ -1,7 +1,7 @@
 module Dodge.Placement.Instance.LightSource.Flicker where
 import Dodge.LevelGen.Data
 import Dodge.Data
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Data.Maybe
 import Control.Lens
 import System.Random
diff --git a/src/Dodge/RadarSweep.hs b/src/Dodge/RadarSweep.hs
index 3422ac0e3..9ad54c526 100644
--- a/src/Dodge/RadarSweep.hs
+++ b/src/Dodge/RadarSweep.hs
@@ -5,7 +5,7 @@ import Color
 import Geometry
 import LensHelp
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Streaming.Prelude as S
 
 aRadarPulse :: Object -> Creature -> World -> World
diff --git a/src/Dodge/Render/HUD.hs b/src/Dodge/Render/HUD.hs
index dcd6cb425..c77b0d9e3 100644
--- a/src/Dodge/Render/HUD.hs
+++ b/src/Dodge/Render/HUD.hs
@@ -21,7 +21,7 @@ import ListHelp
 import qualified Data.Vector as V
 --import Data.Foldable
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 --import qualified Data.Set as S
 --import qualified Data.IntSet as IS
diff --git a/src/Dodge/Render/Lights.hs b/src/Dodge/Render/Lights.hs
index 1ad46a1b6..62f751aa6 100644
--- a/src/Dodge/Render/Lights.hs
+++ b/src/Dodge/Render/Lights.hs
@@ -6,7 +6,7 @@ import Dodge.Data
 import Geometry
 
 import Data.Maybe
-import qualified Data.IntMap.Lazy as IM
+import qualified IntMapHelp as IM
 
 lightsToRender :: Configuration -> World -> [(Point3,Float,Point3)]
 lightsToRender cfig w = mapMaybe getLS (IM.elems $ _lightSources w) 
diff --git a/src/Dodge/Render/ShapePicture.hs b/src/Dodge/Render/ShapePicture.hs
index 9c25ed8b8..4e43c9238 100644
--- a/src/Dodge/Render/ShapePicture.hs
+++ b/src/Dodge/Render/ShapePicture.hs
@@ -39,7 +39,7 @@ import ShortShow
 import Polyhedra
 
 import StreamingHelp
-import qualified Data.IntMap.Strict as IM -- Lazy?
+import qualified IntMapHelp as IM -- Lazy?
 import qualified Data.Map.Strict as M
 import Control.Lens
 import Data.Maybe
diff --git a/src/Dodge/Render/ShapePicture.hs.orig b/src/Dodge/Render/ShapePicture.hs.orig
index 423a191d3..97569e3f4 100644
--- a/src/Dodge/Render/ShapePicture.hs.orig
+++ b/src/Dodge/Render/ShapePicture.hs.orig
@@ -28,7 +28,7 @@ import Geometry.ConvexPoly
 --import Dodge.Base.Collide
 
 --import Data.Foldable
-import qualified Data.IntMap.Strict as IM -- Lazy?
+import qualified IntMapHelp as IM -- Lazy?
 import qualified Data.Map.Strict as M
 --import qualified Data.Set as Set
 import Control.Lens
diff --git a/src/Dodge/Render/Walls.hs b/src/Dodge/Render/Walls.hs
index f3621cde6..52e118ea0 100644
--- a/src/Dodge/Render/Walls.hs
+++ b/src/Dodge/Render/Walls.hs
@@ -12,7 +12,7 @@ import Control.Lens
 import qualified Control.Foldl as L
 import qualified Streaming.Prelude as S
 --import Data.List
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 wallsToDraw
     :: World
     -> ( [((Point2,Point2),Point4)]  ,[((Point2,Point2),Point4)], SPic )
diff --git a/src/Dodge/Room/Airlock.hs b/src/Dodge/Room/Airlock.hs
index 49980bd8f..6f0908150 100644
--- a/src/Dodge/Room/Airlock.hs
+++ b/src/Dodge/Room/Airlock.hs
@@ -14,7 +14,7 @@ import Geometry
 import Picture
 
 --import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 {- | A passage with a switch that opens forward access while closing backwards access. -}
 airlock :: RandomGen g => State g Room
 airlock = takeOne [airlock0,airlock90,airlockCrystal,airlockZ]
diff --git a/src/Dodge/Room/Door.hs b/src/Dodge/Room/Door.hs
index 2c3d88ef5..257884b24 100644
--- a/src/Dodge/Room/Door.hs
+++ b/src/Dodge/Room/Door.hs
@@ -10,7 +10,7 @@ import Dodge.Placement.Instance
 import Color
 
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 --import Control.Lens
 
 door :: Room
diff --git a/src/Dodge/Room/LongDoor.hs b/src/Dodge/Room/LongDoor.hs
index 9576d94dc..86112ea46 100644
--- a/src/Dodge/Room/LongDoor.hs
+++ b/src/Dodge/Room/LongDoor.hs
@@ -30,7 +30,7 @@ import LensHelp
 import qualified Data.Set as S
 import Data.Maybe
 --import Data.Tree
-import qualified Data.IntMap as IM
+import qualified IntMapHelp as IM
 
 twinSlowDoorRoom 
     :: Float    -- ^ Half width
diff --git a/src/Dodge/Room/Procedural.hs b/src/Dodge/Room/Procedural.hs
index e5998f5c6..f35a4aab8 100644
--- a/src/Dodge/Room/Procedural.hs
+++ b/src/Dodge/Room/Procedural.hs
@@ -34,7 +34,7 @@ import Data.Tile
 import LensHelp
 
 import qualified Data.Set as S
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 --import Control.Lens
 -- This will need a cleanup, but it might change a bit first
 {- A simple rectangular room with a light in the center.
diff --git a/src/Dodge/Room/Start.hs b/src/Dodge/Room/Start.hs
index 02a95bc2c..8c954d54d 100644
--- a/src/Dodge/Room/Start.hs
+++ b/src/Dodge/Room/Start.hs
@@ -31,7 +31,7 @@ import LensHelp
 
 --import Data.Maybe
 --import Data.Tree
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 powerFakeout' :: RandomGen g => State g (MetaTree Room String)
 powerFakeout' = tToBTree "powerFakeout'" <$> powerFakeout
diff --git a/src/Dodge/SoundLogic/LoadSound.hs b/src/Dodge/SoundLogic/LoadSound.hs
index 4bd225faf..9b558d9c6 100644
--- a/src/Dodge/SoundLogic/LoadSound.hs
+++ b/src/Dodge/SoundLogic/LoadSound.hs
@@ -5,7 +5,7 @@ module Dodge.SoundLogic.LoadSound
 --import Sound.Data
 import Dodge.SoundLogic.ExternallyGeneratedSounds
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified SDL.Mixer as Mix
 
 loadSound :: (Int,String) -> IO (Int, Mix.Chunk)
diff --git a/src/Dodge/Spark.hs b/src/Dodge/Spark.hs
index ec2a5a567..2596544dc 100644
--- a/src/Dodge/Spark.hs
+++ b/src/Dodge/Spark.hs
@@ -12,7 +12,7 @@ import Geometry
 import LensHelp
 import Color
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Monad.State
 import System.Random
 
diff --git a/src/Dodge/Terminal.hs b/src/Dodge/Terminal.hs
index 726c7544f..00845babe 100644
--- a/src/Dodge/Terminal.hs
+++ b/src/Dodge/Terminal.hs
@@ -14,7 +14,7 @@ import Data.Char
 import Data.Maybe
 import Data.Foldable
 import qualified Data.Map.Strict as M
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Text as T
 --import Text.Read
 
diff --git a/src/Dodge/Tesla/Arc.hs b/src/Dodge/Tesla/Arc.hs
index 6bbd00936..4de475cba 100644
--- a/src/Dodge/Tesla/Arc.hs
+++ b/src/Dodge/Tesla/Arc.hs
@@ -26,11 +26,11 @@ import Dodge.ArcStep
 --import Dodge.Base.Collide
 --import Shape
 
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 --import Data.List (sortOn)
 import MonadHelp
 import Data.Maybe
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 aTeslaArcAt :: Color -> [ArcStep] -> Particle
 aTeslaArcAt col thearc = PtTeslaArc
diff --git a/src/Dodge/Tesla/Arc/Default.hs b/src/Dodge/Tesla/Arc/Default.hs
index 3c3a27c5f..c4f798591 100644
--- a/src/Dodge/Tesla/Arc/Default.hs
+++ b/src/Dodge/Tesla/Arc/Default.hs
@@ -8,7 +8,7 @@ import Shape
 
 import Data.Maybe
 import Data.List (sortOn)
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 defaultArcStep :: RandomGen g => ItemParams -> World -> ArcStep
     -> State g (Maybe ArcStep)
diff --git a/src/Dodge/Update.hs b/src/Dodge/Update.hs
index 98e5bdce2..0d5b16928 100644
--- a/src/Dodge/Update.hs
+++ b/src/Dodge/Update.hs
@@ -36,7 +36,7 @@ import FoldableHelp
 
 import Data.List
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map.Strict as M
 import Control.Applicative
 import qualified Streaming.Prelude as S
diff --git a/src/Dodge/Update/Camera.hs b/src/Dodge/Update/Camera.hs
index f2164928a..c4d8d9d11 100644
--- a/src/Dodge/Update/Camera.hs
+++ b/src/Dodge/Update/Camera.hs
@@ -25,7 +25,7 @@ import qualified Data.Map.Strict as M
 import Data.Maybe
 import Control.Monad
 import qualified Data.Set as Set
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified SDL
 --import Data.Monoid
 --import Data.Semigroup
diff --git a/src/Dodge/Update/WallDamage.hs b/src/Dodge/Update/WallDamage.hs
index 22f969007..9ebb11d46 100644
--- a/src/Dodge/Update/WallDamage.hs
+++ b/src/Dodge/Update/WallDamage.hs
@@ -2,7 +2,7 @@ module Dodge.Update.WallDamage where
 import Dodge.Wall.Damage
 import Dodge.Data
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 import Data.Maybe
 
diff --git a/src/Dodge/Wall/Delete.hs b/src/Dodge/Wall/Delete.hs
index 1ffd702c7..c43a879d9 100644
--- a/src/Dodge/Wall/Delete.hs
+++ b/src/Dodge/Wall/Delete.hs
@@ -6,7 +6,7 @@ import Dodge.Data
 import Dodge.Wall.Zone
 
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.IntSet as IS
 
 deleteWallID :: Int -> World -> World
diff --git a/src/Dodge/Wall/Move.hs b/src/Dodge/Wall/Move.hs
index b727c809a..f1a92335c 100644
--- a/src/Dodge/Wall/Move.hs
+++ b/src/Dodge/Wall/Move.hs
@@ -14,7 +14,7 @@ import Dodge.Wall.Zone
 
 import Data.Maybe
 import Control.Lens
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 moveWallIDUnsafe :: Int -> (Point2,Point2) -> World -> World
 moveWallIDUnsafe wlid wlline w = case w ^? walls . ix wlid of
diff --git a/src/Dodge/Wall/Zone.hs b/src/Dodge/Wall/Zone.hs
index f0035fd7e..831cd9308 100644
--- a/src/Dodge/Wall/Zone.hs
+++ b/src/Dodge/Wall/Zone.hs
@@ -3,7 +3,7 @@ module Dodge.Wall.Zone
 import Dodge.Data
 import Dodge.Zone
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Control.Lens
 --import Data.Foldable
 --import Streaming
diff --git a/src/Dodge/WallCreatureCollisions.hs b/src/Dodge/WallCreatureCollisions.hs
index a49a2d298..11adfd462 100644
--- a/src/Dodge/WallCreatureCollisions.hs
+++ b/src/Dodge/WallCreatureCollisions.hs
@@ -16,7 +16,7 @@ import Data.Monoid
 import Data.Maybe
 import Data.Function
 import Control.Lens
---import qualified Data.IntMap.Strict as IM
+--import qualified IntMapHelp as IM
 
 import qualified Streaming.Prelude as S
 
diff --git a/src/Dodge/Wire.hs b/src/Dodge/Wire.hs
index e14e8bda9..24aa30493 100644
--- a/src/Dodge/Wire.hs
+++ b/src/Dodge/Wire.hs
@@ -9,7 +9,7 @@ import Shape
 import Color
 import Dodge.Room.Foreground
 
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 floorWire :: Point2 -> Point2 -> ForegroundShape
 floorWire a b = defaultForeground
diff --git a/src/Dodge/WorldEvent/Shockwave.hs b/src/Dodge/WorldEvent/Shockwave.hs
index 0915f55cf..7235ac114 100644
--- a/src/Dodge/WorldEvent/Shockwave.hs
+++ b/src/Dodge/WorldEvent/Shockwave.hs
@@ -13,7 +13,7 @@ import Picture
 import LensHelp
 
 --import Data.Foldable
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Streaming.Prelude as S
 -- currently very effective against walls
 makeShockwaveAt 
diff --git a/src/Dodge/Zone/Update.hs b/src/Dodge/Zone/Update.hs
index 3b8cc4b7e..82892e880 100644
--- a/src/Dodge/Zone/Update.hs
+++ b/src/Dodge/Zone/Update.hs
@@ -4,7 +4,7 @@ module Dodge.Zone.Update
 import Dodge.Data.Zoning
 import StreamingHelp
 import qualified Streaming.Prelude as S
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import Geometry
 import LensHelp
 
diff --git a/src/IntMapHelp.hs b/src/IntMapHelp.hs
index c68985086..3e62b2994 100644
--- a/src/IntMapHelp.hs
+++ b/src/IntMapHelp.hs
@@ -1,5 +1,6 @@
+{-# OPTIONS_GHC -Wno-unused-imports #-}
 module IntMapHelp
-    ( module Data.IntMap.Strict
+    ( module Data.Strict.IntMap
     , newKey
     , insertNewKey
     , insertWithNewKeys
@@ -9,7 +10,8 @@ module IntMapHelp
     ) where
 import LensHelp
 --import Data.List hiding (foldr,insert)
-import Data.IntMap.Strict
+import Data.Strict.IntMap
+import Data.Strict.Containers.Lens
 {- | Find a key value one higher than any key in the map, or zero if the map is
  - empty -}
 newKey :: IntMap a -> Int
diff --git a/src/Multiset.hs b/src/Multiset.hs
index eab305df6..8d4fb04b8 100644
--- a/src/Multiset.hs
+++ b/src/Multiset.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE TupleSections #-}
 module Multiset where
 import qualified Data.Map.Strict as M
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.IntSet as IS
 import Control.Monad
 
diff --git a/src/Music.hs b/src/Music.hs
index 651899745..6889c8107 100644
--- a/src/Music.hs
+++ b/src/Music.hs
@@ -2,7 +2,7 @@ module Music
     ( MusicData (..)
     ) where
 import qualified SDL.Mixer as Mix
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 
 newtype MusicData = MusicData
     { _loadedMusic   :: IM.IntMap Mix.Music
diff --git a/src/Sound.hs b/src/Sound.hs
index 358e9ddc4..0fa3a39a7 100644
--- a/src/Sound.hs
+++ b/src/Sound.hs
@@ -24,7 +24,7 @@ import Sound.Data
 
 import qualified SDL.Mixer as Mix
 import Data.Maybe
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 import qualified Data.Map as M
 import qualified Streaming.Prelude as S
 import Control.Monad
diff --git a/src/Sound/Data.hs b/src/Sound/Data.hs
index 06792f58b..08f44915e 100644
--- a/src/Sound/Data.hs
+++ b/src/Sound/Data.hs
@@ -2,7 +2,7 @@
 module Sound.Data
     where
 import qualified SDL.Mixer as Mix
-import qualified Data.IntMap.Strict as IM
+import qualified IntMapHelp as IM
 --import qualified Data.Map.Strict as M
 import Control.Lens
 import Geometry.Data
diff --git a/stack.yaml b/stack.yaml
index b5e08deb4..06ed85354 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -40,6 +40,8 @@ extra-deps:
     #- SDL-0.6.7.0@sha256:9d6ba75c0cab575ec38468c8277803983e985f9622437aeca6a53e6a7337a7d5,2045
 - sdl2-mixer-1.2.0.0@sha256:6a6b5a46c035c9e77eaf9c244e45de9e4a9b9a110890cfeeb9fa72faa2419cef,4497   
 - repa-3.4.1.5@sha256:4d94845e66d668345130f75f5de8f7c69139b91495c8c4b5a825014e8985e2fd,3562
+- strict-containers-0.1@sha256:d751696a8a74e368cf778cf98410b43fcd192d68febd4c691faaac1d6c3ab63f,10591
+- strict-containers-lens-0.1@sha256:97c0e68e2e23578074d41fa45690a9ff7b1d47057ea6635d863af99f0daa2f9d,1103
    #- repa-3.4.1.4@sha256:5a99bde69fe96a18d70aae23f47c8f719b1134558dca3ee5a7c15423b68a132e,3323
    #- sdl2-mixer-1.1.0@sha256:c809aecd91ebf9c759af66eebaa4f45f766f2603c13a73412abfd0bd1e02071a,3067
   #  # for threadscope