Purge Game

Purge is a persistent, multiplayer online, FPS/RPG hybrid powered by a highly modified Lithtech Talon technology. Originally released in 2002, Purge was designed to perform well on the average computer of the day. Any modern PC today should be able to play Purge. Freeform Interactive has now officially made Purge a free game.
Note: Purge requires a registration key to unlock all the class. This is completely and 100% free. There are no strings attached. The key system is still necessary as a unique user identifier for Purge to save your Role-Playing Game character stats on the game servers. When you have installed Purge, simply request a key. The keys are handled by the Purge community now and not by Freeform Interactive.
Official Site: http://www.purgeonline.net/