Bought the game within the first week it came out.
one of the greatest purchases I made, it's still currently in Alpha but still holds a lot of detail.
There are a few physics bugs but none that 'break' the game.
It's only £4.99 or $7-8 (not completely sure on the American price) and I'd say it's definitely worth the money, besides who doesn't want to murder countless numbers of people or sheep?