Back in the history of Mac gaming is Marathon, a classic first person shooter that was a gaming exclusive for Mac users. Since Marathon was a great FPS, PC gamers were jealous. Now that Bungie made it big with Halo they released all three of the Marathon games have been extended and ported over to the Dreamcast. You can download the image here, but be warned that you need a keyboard to play this.
Check out DCEvolution for more. Via Retrogaming with Racketboy.