BATMAN

Get rid of the killer moth:
Pause the game and then press B, A, B and A. It should then fly the 
other way.

Infinite continues:
On the title screen press, Up, Up, Down, Down, Left, Right, Left, Right
then A and B simultaneously. You can now continue the game indefinitely.

Infinite power-ups:
When you come across the falling drop claws, crouch next to their landing
position and punch repeatedly. Each drop claw that you defeat will turn 
into a heart, weapon bonus or point bonus. There are normally three drops
one after the other and then a slight pause, so hurry up and get bonus and
return to your position.