3D Realms has released the promised playable demo (~ 449MB) for Prey, allowing you to try out this imminent sci-fi first-person shooter by Human Head Studios..

This demo contains the first five levels of the single-player campaign along with a pair of deathmatch maps. Word is: "Defy the law of nature with gravity flipping, a feature that allows you to walk on ceilings and turns deathmatch mode upside-down. Explore unreachable areas with wall walking, and transport from one sphere to another through space-bending portals. With all these unique gameplay elements, you don't want to miss this highly anticipated FPS demo!"

The demo can also be found on GameSpot (->download.com), Ausgamers, 3D Gamers, CGO.ro, FileNuts, FileShack, FragLand, Gamezone, GH, GWN, VGPro, WP, YahooGames.