Saw and enjoyed this yesterday. It is a bit of a case of being a premise (Will Smith last man on earth) in search of a film so the final act was disappointing. That said there are a number of good jumpy moments (you'll never be ready for the first one) and lots of camera creeping round door of room not knowing what's on the other side scenes.
Action moves in time between Smith alone in deserted New York and the events leading up to the end of everyone else.
Smith acts well. Think Castaway where Smith is Hanks and a dog is Wilson the basketball. You'll get the idea.
It's quite short and perfectly acceptable multiplex entertainment for a wet afternoon.