Defeat Vamp

Destroy the AV-88 Harrier II

Put an enemy in a locker

Successfully complete level 6

Kill the Leviathan

Kill 50 Chimera by detonating their heatstacks in the Single Player Campaign

Upgrade all weapons in the Single Player Campaign

Successfully complete level 4

Kill an enemy with every weapon in the Single Player Campaign

Kill 100 Chimera with headshots in the Single Player Campaign

Kill an Impaler

Kill 500 Chimera in the Single Player Campaign