Spiral Knights. (Steam Free-To-Play)

Spiral Knights on Steam

Not too bad of a game. You can only use 100 energy until you either buy more or recharge which you get 5 energy per hour.
So pretty much you have to pay to get unlimited energy for doing dungeons/caves.

Here are some screenshots.

Steam Community :: [hg] BooT :: Screenshots[/hg]
Steam Community :: [hg] BooT :: Screenshots[/hg]

Discuss about this game.

I tried it, and the combat was pretty fun. The only thing I didn't like was that there weren't classes, really. Everyone specializes in swords or guns. I found the 100 energy not that hindering like the cash shops in other F2P games.