The Binding Of Issac.

I really want this game. It is pretty cool, and you get lots of awesome powers. Here is the expansion pack trailer. Don't let the little boy character fool you, this is a really scary game.

And it's cheap! Costs about 7 bucks. This new upcoming expansion pack will cost 3 bucks only!
Looks like steam found another good game. Just, it isn't exactly scary, its just kinda emotionally scary.
Also, your character is an irresistible little baby! Just look how adorable! Don't worry, it's kinda funny too.
There are some memes in it too, like trollface and forever alone. Not too famous, but I think this is a pretty good third person dungeon shooter.