Windows XP not supported?

[plutomaniac]

That's what the seller promises. If it doesn't work on XP, then it's false advertising.

Oh yes, maybe they tested the game at XP and saw that it works. Maybe it's just false advertising as Scrap said.

My guess is that almost certainly it will work just fine but as already mentioned no support/fixes can be given in case of problems. Maybe some unofficial fixes/guides like Amnesia and Intel cards. But that's all.