Bronze Cheats:

Beat the game on Easy. This will give you "One Hit Kill" and "Weapons Stay" options in multi-player.

Silver Cheats:

Beat the game on Medium. This will give you "Game Speed" and "Blast Force" option in multi-player, as well as the Bronze cheats.

Gold Cheats:

Beat the game on Hard. This will give you "Infinite Ammo" and "All Weapons" options in multi-player, as well as the Silver cheats.

Game Shark Codes: