The default desktop environment on Ubuntu (Unity) has a problem that causes the framerate to drop in games (
bug #988079). You might want to try starting "Ubuntu Classic (No effects)" or Unity 2D instead for gaming.
Unfortunately third party development for Linux is difficult due to a lack of stable API's. There are often incompatibilities between different Linux distributions, and between different versions of the same distribution - even if they are released just a few months apart. There is also a lack of a standardized way of distributing software that works across different Linux distributions. If there isn't a package for your specific distribution you'll usually end up with a .tar.gz and a howto. That's why you often need to use various hacks and tricks to get third party software working. Hopefully the situation will improve since both Ubuntu and Gnome is aiming for API stability now.