Fix Physics weirdness in Level 3
Fix Physics weirdness in Level 4 (dropping through ground)

Ideas for content:
- Goals:
  - MS Word = Sentenz
  - Powerpoint = WeakClic
  - Minecraft = InfiniMined
  - The "you win"-button
- Minigames:
  - Bullet-Hell
  - Mouse-based games?
- Other:
  - Possibly secrets and alternate paths?