I got this one today as a bonus for buying the Humble Voxatron Debut. This and Blocks that Matter got given to the customers as a bonus, which makes me very, very happy. I’ve know about Isaac for a while and I really liked what I’ve seen on various let’s play videos.
Since I’m still on Avadon, I only gave it a try for now. I managed to finish two or three levels and got killed by one of the bosses. I didn’t unlock anything yet, but I think I’ll play this game quite a bit in the future.