Among the action crowd, certain 2D shooters are legendary. Soldat and Liero are these shooters. Combining fast paced FPS gameplay with side-scrolling graphics and sensibilities, they are incredibly fun to play with friends. Another game can be added to that roster now. Teeworlds is an open-source game much in the same vein as Soldat, except better. Where the two games mentioned earlier are darker and bloodier, Teeworld has a bright atmosphere evocative of the Worms games. Teeworlds also has countless mods, a full-featured map editor, and many improvements you will wonder how other games went without. In short, for the freeware action fan, you'll be hard pressed to find a better multiplayer side-scroller.

[Via TIGSource]