I've had a pretty mixed bag with Steam sale purchases. Blacklist is surprisingly good. Nidhogg would be great if anyone were ever online to play it with. Most of the other stuff is kind of crap. I got bored of Super Hexagon and Risk of Rain five minutes in; Rogue Legacy never seems to actually go anywhere; Magic 2014 is pretty dull but that was expected.
Still Amalur, Payday 2, Natural Selection II and Gone Home to try.