Full Power & 4 way split screen & Ending

First reset the game 35 times.

Full Power
At the weapon status screen enter the code below

4 way split screen
At the title screen enter the code below

Ending
At the level select screen (see separate cheat) enter the code below

Contributed By: real_mukimuki.

Level Select & Invincibility

Level Select
At the Sound Test screen (see separate cheat), select '1F' and enter the code below. You will hear an explosion if it worked.

Invincibility
Choose the level you want to start at and enter the code below

Contributed By: real_mukimuki.