To The Moon will release on Linux and Mac soon, apparently.
Speaking to Polygon, creator Kan Gao said the ports are "not far off".
We've been waiting quite a while, as the PC version launched in September 2012. Gao explained that a legal issue related to the engine held things up, but it has since been resolved and Freebird Games is now making progress.
During the holidays, a free update added 20 minutes of extra content to the award-winning adventure.
To The Moon 2 was announced in March last year, but we haven't heard anything in the interim.