Unlockable Costumes

Complete videogame once using character Detective Barry Crimson.
Unlocks: Detective Barry Crimson's crimson shirt.

Complete game twice using character Detective Barry Crimson.
Unlocks: "I <3 Detective Barry Crimson" t-shirt.

Complete game three times using character Detective Barry Crimson.
Unlocks: "I'm so sick and tired of Detective Barry Crimson" t-shirt.

Complete game without friendly fire.
Unlocks: Eagle Scout badge.

Complete game killing all your fellow soldiers.
Unlocks: Fugitive hobo disguise.

Complete game only pressing B button.
Unlocks: Gray Rainman suit.

Remain married for fifteen years.
Unlocks: Crystal watch.

In Phatal Phighting Loading screen, quickly press up, down, B button, X button, left, right, triangle button, L3 button, right trigger.
Unlocks: Other costume.

Complete game once using female character Stacii.
Unlocks: TEH BOOBIES.

Retro wear
Celebrate 15 years of this videogame franchise with these original unlockable costumes, first introduced in the 1990s.

To activate:
1. From the title screen menu, select "Options."
2. From options menu, select "More Options."
3. Select "Other."
4. From new menu, select "Codes." This option can be found in between "Art Gallery" and "Credits."
5. Enter following 8-digit codes:

T7P0B27D. Unlocks: Parachute pants.
GGU8_ES4. Unlocks: Bootleg Bart Simpsons T-shirt.
PVYY83+Q. Unlocks: Bowling shirt with martini glass logo.
23KD~XD7. Unlocks: Dr. Seuss hat, pacificer, rave whistle.
LR28UHU9. Unlocks: SOY BOMB written on chest.
8GWQZ7TC. Unlocks: Michael Ian Black commenting on your clothes.