Hitman: Sniper Challenge could be described as a "sub-game" of the upcoming instalment in the popular Hitman series--a sub-game that is only available (as of now) through preordering Hitman: Absolution. Sniper Challenge is a short and rather disappointing teaser for the upcoming game, and there would be no justification in charging for it should it go on the Xbox Live marketplace or the Playstation Network store after the release of Absolution. If one didn't know what the Sniper Challenge was, one would assume it's a demo for Absolution, and this fact warrants treatment as such--I would be much satisfied if it were released as a free game or classified as a demo.
The Sniper Challenge takes place on a rooftop in Chicago, overlooking a building across the street that's hosting a rave party of some sort. In the briefing, Diana (and before anyone makes the obvious connection, Sniper Challenge is not connected to Absolution in any way) informs Agent 47 that his target is Richard Strong, Jr., the CEO of weapons manufacturer Stallion Armaments, and his entourage of bodyguards. I'm unaware of whether or not the bodyguards are mandatory or optional targets, as I've always killed them off before going for the main target.
Your only weapon is a silenced, bolt-action sniper rifle that can be upgraded through earning points via kills. Upgrades include a magazine size extension and a faster bolt cycling (increasing its fire speed). I find this to be utterly disappointing. I see no valid reason to not include a weapons loadout menu during the beginning of the mission where players may choose from a selection of sniper rifles (after they're unlocked in-game, naturally) and select attachments such as suppressors, laser sights, extended magazines, etc. I understand Sniper Challenge is supposed to be some sort of whet-your-appetite kind of deal, but it's utterly tasteless.
The scenery of the game is a decent redeeming factor however. The graphics, while not the best of its time, are certainly well done and mildly an improvement in the Hitman series. The Sniper Challenge also features a destructible environment which proves useful for making kills look like accidents, a feature first introduced in Hitman: Blood Money. For instance, shooting the cord of a platform holding barrels will cause them to fall and crush whomever is unfortunate enough to be standing underneath.
While the Sniper Challenge is a somewhat decent game in itself, it poses as a poor preview for Absolution and naturally, wouldn't bode well should it cost anything to play, other than the $5 minimum to cover the preorder of Hitman: Absolution. With Sniper Challenge being practically given away, I wouldn't advise ignoring it because it is fun at most times, but I'll save my energy for the upcoming instalment.