http://www.openclonk.org/"Open Clonk is a multiplayer-action-tactics-skill game. It is often referred to as a mixture of The Settlers and Worms. In a simple 2D antfarm-style landscape, the player controls his crew of Clonks, small but robust humanoid beings. The game encourages free play but the normal goal is to either exploit valuable resources from the earth by building a mine or fight each other on an arena-like map."