This week, I've found the Achievments list for Black Ops on CoDWiki.
The last few achievements are :
“Insert Coin” : Access the terminal and battle the forces of the Cosmic Silverback in Dead Ops Arcade.
Easy Rhino : In Dead Ops Arcade, use a Speed Boost to blast through 20 or more enemies at one time.
The first one mentioned the "Dead Ops Arcade" and I think the achievement is basically just finish the entire campaign and play this mode.
Based on the name,"Dead Ops", I thikn that this is the zombie mode's name.
And the second achievement is the "Easy Rhino", it says "use a Speed Boost to blast through 20 or more enemies at once."
I guess the "Speed Boost" is a new feature, maybe as a power-up or maybe a skill, allows player to walk/run faster.
The enemies maybe refer to "zombies".
If you think that this maybe real, please leave a comment.