I know that it have been in the forums before http://community.gaslampgames.com/threads/where-do-linux-users-purchase-their-games-from.3/#post-18 But it is really a bad idea to put DoD in the USC? In the forum someone says that it would be like making DoD only for XP or only for Windows 7. But people that not uses ubuntu always can use Desura (DoD is there) and/or downloading from the page The people that use ubuntu (like me) loves to their software well integrated and centralised. I think the only thing USC lacks is a mechanism to make the game available to the people that have bought trough the page, something like Desura Keys What do you think?
