If you've never heard of it, it's an indie game created by Edmund M., the same guy who made Super Meat Boy. It's kinda weird and dark at first, but it gets really fun, and I really enjoy it!
I completely agree, this game has already stolen about 110 hours of my life, according to Steam. I'm down to my last handful of achievements. The expansion pack is almost required to fully appreciate how fun (and difficult) this game is, and seeing as both together are only about $7 during a steam sale, this should be something worth checking out.
I love the Binding of Isaac! One of my favorite games to play, and I'm on a never ending quest to get all the items.
Oh man... I might have to check this out! I've heard of it but I never looked into it. I love Super Meat Boy, though, and if it's at all like Zelda like someone else said, I think we have a winner.
I found out about it a few months ago and have since then been obsessed with it. The random generation never gets old and I'm so excited for rebirth!
The binding of Issac is an amazing game. You do have to understand all the biblical references to thoroughly enjoy the game though.