Complete all objectives in single player mode to unlock cheat mode.

God Mode:
Unlock cheat mode, hold Back, and then press X, X, A, B and A to unlock god mode.

Big Heads:
Hold Back and press A, X, B, Y and A during gameplay. A message will confirm correct code entry.

Chicken Heads:
Hold Back and press X, X, Y, A and B during gameplay. A message will confirm correct code entry.

Flat Characters:
Hold Back and press B, A, X, Y and A during gameplay. A message will confirm correct code entry.

Helium Mode:
Hold Back and press X, A, Y, B and X during gameplay. A message will confirm correct code entry.

Slow Motion:
Hold Back and press Y, Y, B, X and A during gameplay. A message will confirm correct code entry.