Aspyr today announced that a free demo version of DOOM 3 (463MB) is now available. “DOOM 3’s dramatic storyline, pulse-pounding action, and incredible graphics, combine to produce the most frightening and gripping gaming experience ever created,” the company says. “DOOM 3 utilizes id Software’s revolutionary new 3D graphics engine to create disturbingly realistic graphics, with never before seen detail and real-time lighting. Players can fight the forces of evil as a lone marine or battle other marines in team or deathmatch-based multiplayer modes.” The DOOM 3 demo lets a single-player explore the first chapter as they move through 3 levels from Mars City.