Beat the game on Easy. This will give you "One Hit Kill" and "Weapons Stay" options in multi-player.
Beat the game on Medium. This will give you "Game Speed" and "Blast Force" option in multi-player, as well as the Bronze 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.
Infinite Health P1 800cbda00064 Infinite Armor P1 800c7f1e0064 Infinite Shotgun & 800c7f3c0064 Super Shotgun Ammo P1 Infinite Machine Gun 800c7f3e0064 & Chaingun Ammo P1 Infinite Grenades & 800c7f400064
Grenade Launcher Ammo P1 Infinite Rocket 800c7f420064
Launcher Ammo P1 Infinite Hyper Blaster & 800c7f440064 BFG Ammo P1 Infinite RailGun Ammo P1 800c7f460064 Super Jump d00c7dd08000 (Press Square) P1 800cbd86fec7
Thanks to Revolution readers Sjoerd Heldens, alex gibson, Kyle Winfield, IGGY, Paul Hand, Evan Peck, and Saiful Rizal!