Reus was a game I wanted to get before, but since it required DirectX10, and I only have 9c with XP, I never got it.

I'm assuming it still isn't compatible (officially) with XP, since you would need an unofficial version of DX10 to make it work?

First I've heard of it. I run it on XP without any problems. Well it's a bit slow since my machine is ancient, but it runs on XP just fine - by which I mean it doesn't appear to require DX10.

Huh, yeah GOG do say that don't they?

Doing some more searching, apparently it DOES require a DX10 compatible graphics card, so it must install DX10 as part of its installation (so you definitely won't have to hunt for and install a dodgy version of DX10 yourself, I never had to). I know for certain that I have XP and that I have run this with my machine.

Also make sure your graphics card is DX10 compatible, and won't have issues, as others have had graphics-related problems. This forum may help: http://forums.abbeygames.com/viewforum.php?f=18&sid=d7fa0c72c87b7422541a6ab6bab570fa

I'd always gone on the assumption that XP couldn't handle DX10 at all, so didn't really think about it until I looked it up... ;)

I'm not sure if it matters but AfterBurner's OSD reports reus.exe is running DX9, not DX10. It's possible they intended to use DX10 or perhaps made it backwards compatible. I'm running Windows 7 with a DX11 compatible GPU so I can't say if it runs on XP though.

The game was made using XNA (at least XNA 4.0 is installed along with the game), I presume it's just that XNA officially supports DX10 and thus some developers list it as a requirement even if their particular game doesn't use/require it, just to be on the safe side or something.