maxwellaguiarsilva, I have Ubuntu 14.04 64-bit as well. If you want a more recent version, look at the first post in this thread. His goes up to 2.1.8, so you can't play online, unfortunately, but you get the new levels on single-player, and you can run custom WADS meant for 2.1.
One caveat, though. On linux, in 2.1.8, the game crashes on the final boss of Castle Eggman Zone. The bug was fixed after the release of it, but the patch didn't make it into the game until the next version. Strangely, this bug was only in the linux version, though, so Win32 versions didn't have that issue. So, after all that's been said, you'll probably have to compile from source to be able to complete the game without using DEVMODE to skip that fight.
Alas, I can't get the newer versions of srb2 to compile at all. Last time I successfully compiled it was 2.1.8 + the patch to fix the crashing.
But, to be totally honest, running the Windows version using wine in linux offers the best experience, even better than using it on real Windows 7! In running both linux game on linux pc OR windows game on windows pc, v-sync doesn't work correctly for me in full screen mode, no matter what settings I set in game or on my NVIDIA OR Intel card (I have an Optimus setup on my laptop). The tearing is horrible in levels like GFZ act 2 with those patterns all over the walls.
But running in wine + using the virtual desktop option and setting it to your monitor's full-screen size + using compiz as your window manager = you can run full-screen with no tearing, and no loss in performance. ^_^