|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.
|Brawl Game Mini-game|
Successfully complete levels 6 through 10 with a three star or greater rank to unlock the Brawl Game mini-game.
The following codes have no effect until you complete both levels with a five star rank on the hardcore difficulty setting to unlock them. Each code has two parts, each of which are unlocked by a specific two levels (for example, completing levels 17 and 18 with a five star rank unlocks the "Invisibility" cheat). When this is done, one half of a code will appear at the bottom of the image that is now unlocked in the "Bonus Features" menu. Once both halves (images) are unlocked, enter one of the following codes at the main menu to activate the corresponding cheat function:
| Result || LEVELS TO COMPLETE || Cheat Code |
|Runner Mode||1, 2||urunfast|
|Silence Mode||3, 4||allrdeaf|
|Helium Hunters||7, 8||theyboom|
|Fully Equipped||9, 10||ugotarms|
|Super Punch||11, 12||uhithard|
|Rabbit Skin||13, 14||bunysuit|
|Monkey Skin||15, 16||hellsuit|
|Piggsy Skin||19, 20||piggsuit|
|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.
|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.
|Grand Theft Auto 3 References|
Towards the end of the game, the journalist on television doing a news report about Starkweather mentions Carcer City's police chief Gary Schaffer and his involvement with Starkweather. In Grand Theft Auto 3, on the Lips 106 radio station, a news report states "In nearby Carcer City, police chief Gary Schaffer's was cleared of corruption charges." It then continues to say "Let's hope those missing witnesses turn up soon."
|Grand Theft Auto: Vice City References|
In the journalist's apartment, in the one room is a blue and white shopping bag with the words "Gash" written on the front of it. This is the same name of a department store in the North Point Mall in Grand Theft Auto: Vice City.
In the Fueled By Hate level go to the junkyard. The car crusher and its surroundings are the same from Grand Theft Auto: Vice City's junkyard.
In the View Of Innocence level, on the second floor in one of the shoot out locations, look for a little counter with the words "Tarbrush Caf" and a little picture of a coffee cup. The Tarbrush Cafe is the location where Tommy and Lance had to destroy in the Cop Land mission in Grand Theft Auto: Vice City.
|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.
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.
|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.
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.
|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.