To get all the weapons, 500 bullets for each weapon, all the keys, and 200 percent armor, simultaneously press Pause + # while playing. Press Pause again to resume play.
During regular game play, simultaneously press Pause and the corresponding button(s):
Levels 1-9: Press Pause + 1 to 9
Level 10: Press Pause + A
Levels 11-19: Press Pause + A + 1 to 9
Level 20: Press Pause + B
Levels 21-24: Press Pause + B + 1 to 4
