I have some niggles!
1. Don't use Movie Maker. At least, don't use that font. Please...
You did well by avoiding the irritating transition effects, but the font and text animations give the impression that you've just uploaded a crappy montage (which you haven't). Try keeping to one simple style. Perhaps use a font that was used in Black Ops itself.
2. I recommend removing the heartbeat sounds from the clips where he looks through the scope. The point of having them in the game is that the character is so utterly focused on holding the rifle still and accurate that everything else is excluded from his senses to the extent that he can hear his own body. Having it in there at the same time as the music detracts from that feeling.
3. Possibly explain what it's about. The impression I got was that the sniper was on a mission to destroy that thing that looked like a radio station near the end, but I'm not sure and I only decided on that about halfway through. Perhaps you could have a few early shots of the radio station thingy being patrolled around by the guards? Maybe also a scene where the sniper kits up in preparation (which could even be the class customisation window).
Other than that, it was good. It probably seems like I'm only feeling critical of it, but that's because I'm just mentioning the things that I think will help.
