Cheat Mode:
When the game begins you have to go to the right. You´ll see an Teddy Bear.
Jump there facing towards the wall and press the O-Button. A slight sound appears.
Go out there and walk in the next room directly to the right (down into the small room) . Press the
O-Button again. Sound again.
Now you´ll have an platform available. Jump there and you´ll reach a playroom. Now the cheats are activated.
During normal gameplay use controller 2 to enter the codes:

Invulnerabiltiy:
X,X,X,X,T,O,X,S

All Weapons:
O,O,O,T,T,X,X

Levelselect:
T,T,T,T,S,S,S,X,X,O