God mode

Successfully complete the game on the "Fetish" difficulty setting, then press Down(2), Circle, Up, Square, Triangle, Square, R2, Up(2), L1, Triangle at the title screen. If you entered the code correctly, the message "God Mode" will appear at the bottom of the screen. Note: The game cannot be saved while this code is enabled.

Use the following trick to save the game while in God mode. Enable the God mode code, then finish a few levels with a three star rank or higher until you get a bonus level (Hard as Nails, Brawl, ect.). Then, play one of the bonus levels, die, and quit. This will reset the codes you enabled. Next, play any easy level and save at one of the check points. You will keep all the stars that you have earned with the cheat codes.

Alternate title screen

Successfully complete the game, then press L1 + L2 + R1 + R2 at the title screen to hear a backwards message being whispered. Note: A new segment of whispering can be heard each time the buttons are pressed.

Hard as Nails mini-game

Successfully complete levels 1 through 5 with a three star or greater rank to unlock the Hard as Nails mini-game.

Brawl Game mini-game
 
Successfully complete levels 6 through 10 with a three star or greater rank to unlock the Brawl Game mini-game.

Monkey See, Monkey Die! mini-game

Successfully complete levels 11 through 15 with a three star or greater rank to unlock the Monkey See, Monkey Die! mini-game.

Time 2 Die mini-game
 
Successfully complete levels 16 through 20 with a three star or greater rank to unlock the Time 2 Die mini-game.

Getting a five star rank
 
Play on the "Hardcore" difficulty setting and either do lots of gruesome executions or get lots of kills, and finish the level as fast as you can. Also, be stealthy and avoid confrontations as much as possible. Fist fights or ruined stealth opportunities make you lose time and lower your ranking.

Opening gates
 
When on a level that requires a crowbar to open a gate, just shoot the lock with a gun. You can now walk through the gate.

Killing Piggsy

To finish off Piggsy, after you stab him three times go up the stairs and lure him onto the grate at the top level. The grate will bend the first time and he will run away. Lure him back upstairs and onto the grate for a second time and he will fall through. Make sure that you are also not on the grate or you will suffer a similar fate as Piggsy.

Early sawed-off shotgun in Born Again level

After you are let out of the execution room, you will soon find yourself in a basketball court where you have to defeat several gang members that are sent out after you. There is an opening in the fence around the court where you will see a posted sign reading "Vote Congressman Matthew R. Dione for Willington Mayor". Under the sign in the tall grass should be a sawed-off shotgun.

Bonus item in Mouth Of Madness level
 
In this level, you must kill the smiley hunter on the tower and bring his body to the guard room. Kill the hunter on the tower and make sure to cut off his head. However, do not bring his body to the guard room (just his head). An intermission sequence will show you entering the guard room with only the head. Starkweather will say "For bringing this head I will leave you a little gift in the next location". Look around for the unknown item.

Gruesome view

When a victim is on the ground begging for his life and before you finish him off, hold R3 and start attacking. The camera angle will then show a partial close-up view through the eyes of the victim, with you swinging away.

Exploding head

In many instances a foe can lose his head in one of the death animations, such as baseball bat level 3 or wire level 3. If you smack a downed opponent in the head, their head will basically explode. If you have severed their head prior then go to smash it in, it will still explode as if the head were still attached to the body.

Transforming head

Hit a save point with a throwable head with you. If you die, it will become a head with a bag wrapped around it.

Floating chainsaw

When you kill Starkweather and Cash puts the chainsaw through his head, Starkweather's corpse falls over. Cash will then put the chainsaw in his stomach. However, sometimes he does not directly get it on his body and you should see the chainsaw floating in mid-air.