Yes! Finally another major game to come to Linux. I really wish this happened more often. My gaming experience in Linux compared to Windows has been better than windows. Linux (Ubuntu) handles fullscreen games much much better than Windows. Also games run slightly faster in Linux on the games that are properly ported to Linux (no Wine wrapper or lazy port).
...and you replaced Windows with Ubuntu, which is just as horrible (from a free software / open source user perspective)...
Although it's nice to hear that more and more games are actually ported to Linux, I personally don't care much about them as long as they are aiming for just one or two distributions. Of course - for publishers it's a bit problematic with Linux operating systems, because there are so many different distributions for different preferences, but I'm a Slackware and OpenSuse guy... and wild horses couldn't ever drag me to installing Mark Shuttleworth's spyware on my machines.
^ the point is: Ubuntu is just as bad as Windows (from a software freedom prespective). "Linux" itself is just a kernel, the actual operating system is built around that kernel. Being a "Linux"-veteran, I don't like what Canonical packs around the kernel. And that's why my choice goes for other Linux-distributions, which stay true to the free software thoughts that actually make Linux so powerful.