Mac Games and More has released a new game for Mac OS X and Windows called
Antigen. The game has been released for free under a Creative Commons license.
Antigen harkens back to the good old days of arcade games: It’s a “shmup,” or shoot ‘em up-style arcade game featuring unlimited levels. In Antigen, you maneuver a ship around a world of germs, viruses, bacteria and toxins, annihilating them wherever you find them.
A radar minimap gives you an overview of enemies approaching the ship, and counters indicate which wave is being played, how many enemies are left and how many lives you have remaining. Some of the substances you destroy will throw bonuses your way that you can then use to your advantage.