Underrated indie games?

What makes a game underrated?

Skyrim. Never got enough praise.

Ace of Spades

English Country Tune.
I love puzzle games, and in my opinion it's pretty awesome for an indie game. No story, lots of levels, very freakin' challenging. It only needs Steam cards just to be perfect!.

EDIT: I consider it underrated because pretty much no one got to play it, and it came on a recent humble bundle.