Strange

> OS: Ubuntu 12.04 or later

1) Why Ubuntu?
2) Ubuntu is not OS, GNU/Linux is OS

Forums: 

afaik:

Game is made for Steam >> Steamlib & Steam is build against ubuntu 12.* >> steam bootstraps ubuntu 12 on every Linux device >> Games on Steam need to be build against steamlib >= Steam & their stuff is only supported on ubuntu 12(since it is build against it like all steamlib games)