Rogue Trooper - Unlimited supplies

Unlimited health:
Press Left, Right, Up, Down, L3, Square at the "Extra" menu

Extreme ragdoll:
Press Up, Up, Up, R2, R2, R2, Up at the "Extra" menu.

Unlock Extreme ragdoll:
Beat the game once

Low gravity ragdoll:
Press Square, Square, Square, Circle, Circle, Circle, Up, Down at the "Extra" menu

Unlock Low gravity ragdoll:
Beat the game once

Hippy blood:
Press L2, Right, Circle, Down, R1, Select at the "Extra" menu

Unlock Hippy Blood:
Beat the game once

Unlock Level Select:
Clear one level and you can select it from the cheat menu

Unlock Massacre Difficulty:
Beat the game once on any difficulty

All weapons and upgrades:
Successfully complete the game. Instead of starting a new game, use the "Level select" cheat and start on the first level to keep all your weapons and upgrades from the previous game.