Dead Ops Arcade

In the zombies menu it’s the option blacked that’s still blacked out. To get this mini-game, enter “DOA” at the computer command terminal. You’ll unlock a straight-ahead, two-stick, retro zombie shooter with space gorillas and helicopters at no extra charge! Dead Ops Arcade will always be available after you enter “DOA”, and it supports co-op.

Fun Fact 1: This easter egg unlocks the “Insert Coin” trophy/achievement,

Fun Fact 2: Kill 20 or more zombies at once in Dead Ops Arcade using Speed Boost power-up and the “Easy Rhino” trophy/achievement is unlocked.