HSC puts you in the shoes of the infamous Agent 47. Your mission : Kill a VIP and ALL 14 of his bodyguards. Simple enough right? WRONG. He's on a rooftop party and constantly on the move. The game really does provide a good challenge and it will take you a couple of playthroughs to figure it out. You also have a 15 minute time frame within which to complete your mission.(took me 4.5 on my longest playthrough)
The game does a great job of showing off the final game; Hitman Absolution. The Graphics, the mechanics and gameplay. Its like a demo that keeps you coming back again again. While going about your mission you need to keep in mind who can hear the impact of the shot, Line of sight of the other guards and of course you have to compensate for their movement and the amount of time your bullet will travel. I really liked the sniping mechanics, you have to pull the trigger down gently to slow down time and the scope sway but you only have a second before you get out of breathe(no super human ME3 sniping here). There's also the added aspect of taking out targets in Places where their body will be hidden; ie it falls into the pool, bushes or even off the ledge.
Despite the fact there is only one level, i find myself going back for more. Trying out the different challenges(There's even one for shooting pigeons), or maybe just picking off the targets in a different order. You can even try Blitzing through; there's a challenge for doing it under 150 seconds (its hard, I've tried)
While it shows off only one aspect of the game(The only one i am probably interested in), the loading screen is riddled with gameplay videos and cutscenes from the final game, which actually have me quite excited. I feel that this would have been more useful as a demo for enticing people into buying the game, rather than a pre order bonus. However if you are planning to buy the game, I'd recommend pre ordering it because HSC is totally worth it.