Unlimted Health:
During play, press Start to pause and press , Left, , Right, R2, L2, Up, Up.

All Weapons:
During play, press Start to pause and press Up, Down, Right, Left, R1, R2, L1, L2.

Inf Health and Necroplasm:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, RIGHT, LEFT, DOWN, UP

All weapons:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, LEFT, RIGHT, LEFT, LEFT

Inf ammo:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, UP, LEFT, DOWN, RIGHT

Inf Necroplasm:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, DOWN, LEFT, UP, RIGHT

No blood:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, UP, UP, UP, UP.

Unlock all comics:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, RIGHT, LEFT, LEFT, UP

All missions:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, LEFT, LEFT, RIGHT, RIGHT

Encyclopedia:
During play, press Start to pause and press UP, DOWN, LEFT, RIGHT, LEFT,RIGHT, UP, DOWN

Thanks to Revolution readers Mary and Dragon Lord!