SlackBuildsOrg/games/bloodfrontier

Blood Frontier is a Free and Open Source game using SDL and OpenGL
which allows it to be ported to many platforms.
The game is a single-player and multi-player first-person shooter,
built as a total conversion of Cube Engine 2, which lends itself
toward a balanced gameplay, completely at the control of map makers,
while maintaining a general theme of tactics and low gravity.