Separate out concrete part of world

src/Dodge/Projectile/Create.hs

@@ -22,7 +22,7 @@ fireShell it cr = makeShell it cr
     spinamount = _shellSpinAmount params
     thrustdelay = _shellThrustDelay params
 makeShell :: Item -> Creature -> [ProjectileUpdate] -> World -> World
-makeShell it cr theupdate w = w & projectiles %~ IM.insert i Shell 
+makeShell it cr theupdate w = w & cWorld . projectiles %~ IM.insert i Shell 
     { _prjPos = pos
     , _prjZ   = 20
     , _prjStartPos = pos
@@ -38,7 +38,7 @@ makeShell it cr theupdate w = w & projectiles %~ IM.insert i Shell
     , _prjMITID = _itID it
     }
   where
-    i = IM.newKey $ _props w
+    i = IM.newKey $ _props (_cWorld w)
     dir = _crDir cr
     pos = _crPos cr +.+ rotateV dir (V2 (_crRad cr + 1) 0)
     am = _itConsumption it