Rogue Trooper - Unlimited supplies

Unlimited health:
Press Left, Right, Up, Down, click Left Analog-stick, X at the "Extra" menu.

Extreme ragdoll:
Press Up, Up, Up, Black, Black, Black, Up at the "Extra" menu

Unlock Extreme ragdoll:
Beat the game once

Low gravity ragdoll:
Press X, X, X, B, B, B, Up, Down at the "Extra" menu.

Unlock Low gravity ragdoll:
Beat the game once

Hippy blood:
Press White, Right, B, Down, R, Back 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.