Hitman [official site] is so close you can almost see the reflection of your face in his highly polished bonce. As you've probably gathered by now, the game itself will be released episodically, and the initial release will only include one sandbox location - Paris. The beta contains two different missions, however, set in a secret facility. The first of those missions is a set, recreating a party on board a yacht, and ol' 47 has to sneak on board as part of his training. An origin story of sorts.
I like that 47's incredible "skills and reflexes" are depicted as climbing through a window and kicking an unsuspecting man in the back of the knee. That's the sort of thing I just about reckon I could pull off if I was in a terrible mood. I'd be a bit worried about actually doing any real damage to the target though because I'd be wearing slippers to maximise my sneakiness.
Preordering the game provides access to the beta on February 19th. That beta includes the above-mentioned yacht mission and a recreation of another historical hit, set in and around a hangar. You'll be able to play until the 22nd, at which point the beta ends, and you'll have to wait until March 11th to sneak through the prologue again. There are full details about the whole package here, including mention of the 4.7gb install size. Whopper.
As for the initial launch itself, we'll have more details soon. It may only contain one location, along with the smaller prologue missions, but it will contain plenty of possible targets: a few exist for story reasons but almost everybody else can be creatively murdered as part of the Contracts mode, carried over from Absolution. That means you can create your own hits, by selecting specific weaponry, disguises and targets, creating new goals to be shared online. It also means you can pretend that you meant to kill that one waiter because you thought it'd be a challenge, not just because he looked at you funny.