For all these cheats goto the "mission select screen" and choose possible or impossible. If done correctly you will hear "There That's Better".

9mm Gun w/ 30 Rounds:
Press R, L, Down C, Up C, Up C

Small Rocket Launcher w/ Thirty Rounds:
R, L, Left C, Right C, Down C

Turbo Mode Code:
Up C, Z, Up C, Z, Up C

7.65 Silencer w/ Thirty Rounds:
Press Up C, L, Right C, Left C, Up C

Uzi W/ 30 Rounds:
Press Right C, Left C, Right C, Down C, R

Total Kids:
Down C, Up C, R, L, Z

Invinciblity:
R,Z,C-Down,R, C-down

Infinite Ammo:
C-up,Z,C-left,Z,L
Thanks to John B.


BIG FEET:
Down C, R, Z, Right C, Left C

BIG HEAD:
Down C, R, C Up, L, Left C

GIANT HEAD:
Down C, L, Up C, Right C, L

*If you use these codes you may not be able to to complete some missions. To return to normal, the game must be reset*