Unlimited lives
Press Right, Right, Up, Left, Up, Right, Down , B , A , Select, Start and Start again at the title Screen.

Unlock Butch
Successfully complete challenge mode as Tyke.

Unlock Ducking
Successfully complete challenge mode as Nibbles.

Unlock Lion
Successfully complete challenge mode as Butch.

Unlock Nibbles
Successfully complete challenge mode as Spike.

Play as Spike
Successfully complete challenge mode as Tom.

Unlock Tyke
Successfully complete challenge mode as Jerry.

Disable Robot Cat
Successfully complete challenge mode as Lion.

Secret weapons
On Lungens And Dragons, hit anything that can be destroyed. When it says "Map destroyed", look for the sword in the rock to find the secret weapon. The same can be done on all levels for different weapons. Note: If you use Jerry, Nibbles. or Tom, you may get a costume on Lungens And Dragons. On the western level, you can unlock a costume with Tom, Nibbles, and Spike.