You are currently running the Mesa Software Renderer for 3D which makes
playing games with 3D (like Tux Racer, Open Arena, etc) very slow.
I can not comment on your desktop experience but for 3D you will most likely
not be able to play any 3D games on Trisquel. Pure software based renderer
and video playback on the other hand rely on good acceleration extensions of
your x-Server.
If you are running pure Vesa things turn out to be slow. You can check your
Xorg.0.log to find out which Xserver you are running.
Running a desktop on pure Vesa really sucks. I had the same experience with
the Atom-based PC I build for my daughter which had the cumbersome
PowerVR-based GPU integrated. Even very small resolution videos could not
play back without visual corruption :(
