Clipping and all puzzle items

Get all the puzzle items Top C, Left C (three times), Right C, Bottom C (two times)

Clipping (you can walk through walls) Top C (20 times), Bottom C

Start your game. You can pick any play mode (normal, co-op or deathmatch) and can have any number of players. Once the game is started or loaded, press start to pause the game. Press: Top C, Bottom C, Left C, Right C. If done correctly, you'll see Cheat appear at the bottom of the menu. Go into the Cheat Menu. The following code must be done rather quickly inside the Cheat Menu. If you pause for even a second, the codes will not work.

Cheat Menu

God Mode (invincibility):
Left C, Right C, Bottom C

Visit (level select):
Left C, Left C, Right C, Right C, Bottom C, Top C

Butcher (kills all enemies currently on-screen):
Bottom C, Top C, Left C, Left C

Health (gives you full health):
Left C, Top C, Bottom C, Bottom C

The codes listed underneath the "Collect Sub-Menu" can be inputed anywhere, but you have to go to the Collect Sub-Menu to use them. If you input the code correctly, you'll hear a "swooshing" sound. If the code is invalid, you'll hear a "Hmmm..." sound.

Collect Sub-Menu

All Keys:
Bottom C, Top C, Left C, Right C

All Artifacts:
Top C, Right C, Bottom C, Top C

All Weapons:
Right C, Top C, Bottom C, Bottom C