To play as Mr. Phatt:

While fighting Mr. Phatt, finish him off with a combo
at does at least 48 points of damage. Once he's
unlocked, you can select Mr. Phatt on the Character
Selection screen.


To play as Abaddon:

Complete the entire game in Captain difficulty mode.
Once he's unlocked, you can select Abaddon on the
Character Selection screen.

To play as Agent 326:
Beat the Cephalapods (end of game bosses) with a final
score of at least 1,000,000 points.

To play as Overseer:
Beat the game with all of the NON-hidden characters -
make sure to save after you win with each guy.

God Mode: During gameplay, hit
L1, R1, L1, R1, UP, DOWN, LEFT, RIGHT.

Quad Damage: During gameplay, hit
R1, R2, R1, R2, UP, DOWN, UP, DOWN.

All Weapons: During gameplay, hit
L1, R1, L1, R1, UP, DOWN, LEFT, DOWN