Hedgewars

Each player controls a team of up to eight hedgehogs. During the course of the game, players take turns with one of their hedgehogs. They then use whatever tools and weapons are available to attack and kill the opponents' hedgehogs, thereby winning the game. Hedgehogs may move around the terrain in a variety of ways, normally by walking and jumping but also by using particular tools such as the rope or parachute, to move to otherwise inaccessible areas. Each turn is time-limited to ensure that players do not hold up the game with excessive thinking or moving. It's like Worms, but with Hedgehogs and it's free and open source.