Here are the three secret achievements you can earn in Call of Duty: Black Ops for the Xbox 360.
Check out my other guide for the full list of Call of Duty: Black Ops achievements.
Eaten by a Grue (15 points) – Play Zork on the terminal
Just Ask Me Nicely (15 points) – Break free from the torture chair
See Me, Stab Me, Heal Me (15 points) – Fire a Pack-a-Punched Ballistic Knife at a downed ally to revive them from a distance
If you need help with these, the first two can be answered in my how to unlock zork guide.
For the third one, that is referring to a weapon in the Presidential Zombie Mode, which can be unlocked by completing the game on any difficulty, or by using a code on the computer terminal. You need to use the Pack-a-Punch machine in zombie mode to upgrade the Ballistic Knife into The Krause Refibrillator, and revive an ally with it from a distance.
