Apocalypse

Level select:
Pause game play, then hold L1 and press Triangle, Up, X, Down. The sound of a gun will confirm correct code entry. Choose the "Exit" option to access the new level select option at the main menu.

Check point skip:
Pause game play, then hold L1, press Triangle, Square, Circle, X to advance to the next check point. The sound of a gun will confirm correct code entry.

Invincibility:
Pause game play, then hold L1 and press Down, Up, Left(2), Triangle, Up, Right, Down. The sound of a gun will confirm correct code entry.

Full health:
Pause game play, then hold L1 and press Square, X, Triangle, Circle. The sound of a gun will confirm correct code entry. Alternatively, pause game play, then hold L1 and press X, Triangle, Circle. The sound of a gun will confirm correct code entry.

All weapons:
Pause game play, then hold L1 and press Square, Circle, Up, Down, X, Square. The sound of a gun will confirm correct code entry.

Unlimited lives:
Pause game play, then hold L1 and press Triangle, Circle, X, Square. The sound of a gun will confirm correct code entry.

Continue from last location:
Resume the game after losing a life. Then, pause game play, hold L1 and press Square, Circle, X. The sound of a gun will confirm correct code entry.

Bottomless falls:
Pause game play, then hold L1 and press X(6). The sound of a gun will confirm correct code entry. Falls will never end while this code is enabled. Repeat code entry to return to normal mode.

Disable weapon and health display:
Pause game play, then hold L1 and press Up, Square, Up, X. The sound of a gun will confirm correct code entry.

Debug mode:
Pause game play, then hold L1 and press Down(2), Triangle. The sound of a gun will confirm correct code entry.

Apocalypse (Game Shark)
Codes Made & Tested on 2.3 Version Game Shark