Predator

Skip Big Mode levels:
Note: This requires a Famicom joystick connected to the expansion port. At the splash screen before entering one of the "Big Mode" stages, hold Joystick Down, hold Up on controller one and quickly tap A on controller one. You should advance to the next Small Mode level. Alternately, press Up + Down while playing the game on an emulator.

Skip Small Mode levels:
Note: This requires a Famicom joystick connected to the expansion port. Hold Joystick Left and hold Right + A on controller one during game play on a Small Mode level. Alternately, press Left + Right while playing the game on an emulator.

Suicide:
Pause game play and press B if your character becomes trapped.