Based on the diffs you've shared, I can see that we've already made some modifications to the terrain-related functionality. However, I still need to see the full contents of the other files you mentioned to provide a comprehensive implementation. Could you please share the full contents of:

1. index.html
2. game.js
3. render.js
4. ai.js
5. events.js

The diffs show that we've added:
- A new terrain.js file with Perlin noise implementation
- Updated utils.js to handle water movement penalties
- Updated ai.js to handle water movement

To complete the implementation, I'll need to see the other files to ensure we:
- Add terrain drawing in render.js
- Prevent building on water in events.js
- Add water movement constants in game.js
- Update AI behaviors to avoid water in ai.js

Could you please share those files so I can provide a complete implementation?

ai.js

@@ -722,11 +722,18 @@ function moveAway(obj, tx, ty, speed=0.4) {
   let dx = obj.x - tx;
   let dy = obj.y - ty;
   let dist = Math.sqrt(dx*dx + dy*dy);
+  
+  // Apply water movement penalty if in water
+  let actualSpeed = speed;
+  if (isWater(obj.x, obj.y)) {
+    actualSpeed *= WATER_MOVEMENT_PENALTY;
+  }
+  
   if(dist > 1) {
-    obj.vx = (dx/dist) * speed;
-    obj.vy = (dy/dist) * speed;
+    obj.vx = (dx/dist) * actualSpeed;
+    obj.vy = (dy/dist) * actualSpeed;
   } else {
-    obj.vx = (Math.random() - 0.5) * speed;
-    obj.vy = (Math.random() - 0.5) * speed;
+    obj.vx = (Math.random() - 0.5) * actualSpeed;
+    obj.vy = (Math.random() - 0.5) * actualSpeed;
   }
 }