Level passwords
02 - Bridge - FLLNGDWN
03 - Fridge - GTMLK
04 - Freezer - CHLLBB
05 - Inside - Wall - CLSNGN
06 - Graveyard - DGTHS
07 - Castle - FRNKNSTN
08 - Tan - Base - BDBZ
09 - Revenge - LBBCK
10 - Desk - DSKJB
11 - Bed - GTSLP
12 - Blue - Town - SMLLVLL
13 - Cashier - CHRGT
14 - Train - NTBRT
15 - Rockets - RDGLR
16 - Pool - Table - FSTNLS
17 - Pinball - Table - WHSWZRD
Tin Foil Uniform
Go to the "input code" screen, and then type in "tnmn" While it looks like normal body armor, don't be fooled. It isn't.
All Weapons
Your Password: GBZRK.
Max Ammo
Your Password: SLGFST.
Play as General Plastro
Your Password: PLSTRLVSVG.
Play as Vikki
Your Password: GRNGRLRX.
Display Debug Info
Your Password: THDTST.
Mini Mode
Your Password: DRVLLVSMM.