All codes have to be entered in the cheat menu.

 Effect:                                      Code:
|====================================================|
|Master code:                                 FMNFB  |
|----------------------------------------------------|
|Invincibility:                               EMERPUS|
|----------------------------------------------------|
|All available weapons:                       TEXAS  |
|----------------------------------------------------|
|Unlimited ammunition:                        MADMAN |
|----------------------------------------------------|
|Level select:                                SELLOUT|
|----------------------------------------------------|
|Invisibility:                                SLLEWGH|
|----------------------------------------------------|
|Big head mode:                               HEID   |
|----------------------------------------------------|
|Zoo mode:                                    ZOO    |
|----------------------------------------------------|
|Demo mode and target mini-game:              HUNTER |
|----------------------------------------------------|