http://kotaku.com/gaming/vista-view/...-xp-272052.php
Turns out this "Vista-required, DirectX 10 only" video-game that noone purchased (some because of a dislike of the license-abuse, others due to no single-player, and still others because of it's Vista-only nature) has had an unofficial patch released by software cracking group Razor1911. Apparently runs just fine on DirectX 9 on XP once you remove the files that say "don't install on XP"