Clean Hospital:
Save the game & reload it again when the hospital becomes full. All of the garbage & patients will disappear.

No More Rats:
If there are rats, just put a plant in front of the hole.

Level Passwords:
2 - X, Circle, Square, Triangle, Triangle, Circle, Square, X.
3 - Circle, Circle, Triangle, Square, X, Triangle, Circle, Triangle.
4 - Square, Triangle, Circle, Square, X, X, Triangle, Circle.
5 - Circle, Triangle, Square, Circle, X, Triangle, Circle, Square.
6 - Square, Triangle, Square, Circle, X, Square, X, Circle.
7 - X, Triangle, Triangle, Circle, X, Square, Triangle, Circle.
8 - Triangle, Square, Circle, Triangle, Circle, Square, X, ?.