From the guys who are making that Overgroth game
[yt]http://www.youtube.com/watch?v=GCThInmzjXw[/yt]
They made it as part of a, make a game in so many days.
I like all of the ideas that guy was talking about.
Wolfire also did Lugaru, and they're responsible for the Humble Bundles.
I just tried playing this for an hour. It's really neat but really really awful.