Hi guys,
What do you think about aт idea to put the game on Steam Greenlight. The game still can be free, open source and NO DRM (DRM in Steam is optional), but with Steam audience you can increase a number of gamers, also you can add features like Steam Achievements and Steam Workshop for user levels and skins.
My company (General Arcade) worked on Duke Nukem 3D: Megaton Edition, Shadow Warrior Classic Redux and Marc Eckō's Getting Up for Steam. So I can help you with Steamworks integration and OSX builds.