Fixed errors in documentation for level creation. Fixed some save loading bugs.

levels/README.md

@@ -291,13 +291,13 @@ The `maximum_skulls` setting controls how many skulls can be falling simultaneou
     "x": 55,
     "y": 0,
     "type": "catapult",
-    "fire_interval": 4000,
+    "fireInterval": 4000,
     "range": 25
 }
 ```
 
 **Properties:**
-- `fire_interval`: Milliseconds between shots
+- `fireInterval`: Milliseconds between shots (note: camelCase, not snake_case)
 - `range`: How far the catapult can shoot
 
 #### Spider Web
@@ -660,8 +660,7 @@ Here's how to transform a Halloween level into a Christmas level using sound ove
             "type": "grave",
             "item": "shin_bone",
             "sound_overrides": {
-                "base": "snow_pile",
-                "item": "candy_cane"
+                    "item": "candy_cane"
             }
         },
         {
@@ -682,7 +681,7 @@ Here's how to transform a Halloween level into a Christmas level using sound ove
 - Weapons sound winter-themed when attacking
 - "Catapult" becomes "Snowball Launcher" with appropriate launch sounds
 - "Skull Storm" becomes "Snowball Storm"
-- "Graves" become "Snow Piles" containing "Candy Canes" instead of "Shin Bones"
+- "Graves" containing "Candy Canes" instead of "Shin Bones" (sound override only - base grave sound unchanged)
 - "Grasping Hands" becomes "Avalanche" with snow-themed death messages
 - All mechanics remain identical - only audio and messaging changes
 
@@ -767,7 +766,7 @@ Here's a comprehensive example showing multiple advanced features:
             "x": 100,
             "y": 0,
             "type": "catapult",
-            "fire_interval": 3000,
+            "fireInterval": 3000,
             "range": 30
         },
         {