This is an upcoming browser-based free-to-play game. The concept art I've seen looks vaguely steampunky, the overall theme seems to be US Old West. It's tough to say how this will play based on the limited assets but I know at least a couple of you guys will be interested in seeing how it develops.
There is a teaser trailer: http://www.youtube.com/watch?feature=player_embedded&v=1wSYYNbjcoQ#!