I don't have much experience with indie games (I'd like to gain more...), but one that I've been playing a lot and beat the main adventure mode of is Copy Kitty, made by Entanma Project. The creators are actually acquaintances of mine, and I've been trying to convince them to port the game to the Ouya, but they don't seem to think it would be worth it.
I played a bit of 'Fireburst' last night. It was nicely polished and comes off as a hopeful MotorStorm clone.
Sadly, while it's indeed polished nicely, the driving mechanics fall well short of modern, and the destruction mechanics feel out of place. Then for some reason it's got a game mode where the controls reversed called 'why the hell am I still playing this?'
Still, a pretty game that cost me $2.50, and it kept me reasonably happy for a couple hours. That's better than a lot of mainstream games do for me.