So much for being a Windows Vista exclusive! Valve has announced that Geometry Wars: Retro Evolved will be blasting onto Steam, the company's downloadable games portal, for Windows XP users this coming Friday.

Initially set to be part of Microsoft's Vista-only casual games push, the Bizarre Creations-developed shooter will be made available for the ridiculously low price of...wait for it... $2.50 USD! Of course, though, if you purchased the game via Windows XP, you're going to miss out on any stupendous Achievements that the Vista version will offer.

"With over 13 million active accounts, Steam is the ideal platform for launching Geometry Wars: Retro Evolved for Windows XP," said Martyn Chudley, Creative Director at Bizarre Creations. "We hope to continue the success of Geometry Wars by introducing its award-winning gameplay to one of gaming's largest communities."

Geometry Wars: Retro Evolved is also currently in development for the Nintendo Wii and Nintendo DS, but if you can't wait for those versions to arrive, then, considering its stupidly low price, you'd be silly not to invest the princely sum of $2.50 on this Friday's PC edition.