Pretty cool little "side game". I bought the Hitman: complete series package on sale for 80% off. The package included every Hitman game that's been released for PC so far, plus all of the available DC. I paid $8(!) for 5 full games, this "mini game" and all of the DC. Literally hundreds of hours worth of game play for the price of a McDonald's value meal. You can't beat that. I played Sniper Challenge while I waited for my other 5 games to download and it was a perfect way to kill a couple hours while waiting to play the entire series.
I've since played the first game, Hitman Contracts a bit and if the other 4 games are anything like that, I'm in for a hell of a good time. According to other reviews, I think $8 was a freaking steal. In fact, full price would have been worth it IMO as the games are pretty cheap BEFORE the discount. Seriously, if you catch this deal when/if it happens again, JUMP ON IT.
I'm going to give Sniper Challenge 8/10. For the price and the fact that it's a mini-game, there is a lot going on here and tons of replayability just to see how high of a score you can get and figure out the best way to accomplish your mission without being detected. There are also side quests like looking for a hidden ninja and shooting hidden rubber duckies. Oh and, you can unlock items for Hitman Absolution by accomplishing tasks in this game. I haven't started Absolution yet so I can't say whether the items are useful or reskins or what but I think it's a pretty cool idea regardless.