Cheats are entered under the options menu,

All maps:
Enter GiveMeTheMaps as a case-sensitive code. You'll have to delete your profile if you want to disable it.

Feral Attack In Earlier Levels:
FeralAttack

Infinite Feral Attacks:
Bloodlust

Infinite Ammo:
UnleashHell

Restore Health:
ImJackCarver

Level Select:
At the Arcade Mode character selection screen enter the following code to be able to change levels:
Hold Down + Left, then Press B + Start.

Start with 9 Continues:
You can begin the game with 9 continues if you enter the following code at the Arcade Mode character selection screen:
Hold Down + Left, then Hold A + C, then release all four buttons and select a character.