Unlock the following modes by performing the corresponding tasks:

CHEAT FUNCTION - CHEAT CODE
Invisibility - Get 300 kills as Jigsaw in multiplayer.
Invulnerability - Get 300 kills as Silver Sable in multiplayer.
Regenerator - Get 225 kills as Barracuda in multiplayer.
Sprint for Life - Beat Story Mode level 1.
Weapon Upgrade - Beat Story Mode level 3.
Berserk - Perform 250 kills using the Rhino in multiplayer.
Blood Gain - Perform 150 kills using the CMG in multiplayer.
Link Feeder - Perform 300 kills using the Enforcer M8 in multiplayer.
Motion Sensor - Perform 175 kills as Microchip in multiplayer.
Rampage - Perform 275 headshots in multiplayer.
Thick Plates - Complete story mode level 2.