Is that the guy who was unable to install Ubuntu properly, so he declared that supporting Linux versions of his game is not worth the effort? Color me disinterested. "No Tux, no bucks."
Frankly, Ubuntu 15.04 and 15.whatever_the_last_release_was have been really, really, really bad. I say this as a gamer, Linux power user, and sysadmin who's been using various flavors of Linux for ~fifteen years and who's quite happy managing his Gentoo Linux boxes, but really happy when he finds a largely-hands-off distro, because that means he can recommend a distro to his friends.
What's more, if you are using Ubuntu 15.latest, Steam doesn't work out of the box. It won't start. You get no error messages or anything. You have to move a bundled copy of -IIRC- glibc out of the way before Steam will work. Reports on the interwebs indicate that the moved file comes back when the Steam client updates itself, so this isn't a permanent fix!
Maybe Valve can't be arsed to target anything other than SteamOS, but it's not a good sign when the company that's -arguably- doing the most good for Linux gaming out of anyone out there doesn't ship a client that works on the latest version of one of the more (if not the most) popular Linux distros.
I'mma have to make a note to go back and remind myself about how dynamic linking and .so versioning works on Linux. I had thought that the tools to make this shit work correctly were widespread and relatively easy to use, but the state of Linux gaming leads me to question my memory. :/