Go to the terminal in the main screen and type in doa.
It unlocks the 3rd zombie mode. It is kinda stupid at first, but I'll get better
You go to the terminal and punch in DOA you'll unlock a level called dead ops arcade (the last level)
When you get to level 10 you can unlock it, then maybe level 20.... 25 to unlock the 3rd machine.
between 1st and the 3rd of march
black mambas are 3rd consumers
3rd prestige
You unlock a new class every other prestige. So 1st, 3rd, 5th, 7th, 9th.
As soon as you start the game you press start then where you see the campaign, multiplayer, zombies, and options buttons, push LT and RT rapidly to get out of your chair. then you walk behind you where you will see a computer. push X then type doa and then push enter. then you will start in the game.
If you mean adamantite, that can be found on any level of the 3rd mine. You can research on how to unlock the mines, but adamantite is randomly thrown in with the rocks that you smash with the hammer on every level of that mine.
costumes! get 25/30 emblems to unlock chris's s.t.a.r.s costume. get 30/30 emblems to unlock sheva's tribal costume. TIP look in every gap,corner like that one in the villlage of the 3rd level hardley noticibly in a very small crevice and the one at the start of the 3rd level hung in front of you on the wall
On the main menu, Tap L2-R2-L2-R2 (or LT-RT(xbox) or Space (pc) or shake the mote and nunchuk (wii)) and look around, you will see a Computer. interact w/ it and type in DOA. You'll also earn 2 achievments.
Break away from the torture chair, and go to the computer. Type DOA in. You should unlock Dead Ops Arcade.