This is what I get:

This is what I should be getting:

Ignoring the names and brightness, I think it's clear what is the problem.
I have Win XP, 64 X2 dual core, 2.11 Ghz and 1 GB of RAM.
It's not a super computer but it can run the game without any problems -I haven't experienced any crashes- but the pixels distortion... it kills it.