The latest edition of Official Xbox Magazine, October 2006, apparently has a demo disc containing a playable version of F.E.A.R.
F.E.A.R. (First Encounter Assault Recon) is an award-winning first-person shooter featuring an intense combat experience with a rich atmosphere and an engaging story. F.E.A.R. immerses you in a unique blend of stylized first person combat and supernatural horror in which you are an elite soldier trained to deal with situations that are unexplainable.
Take on the role of the point man in the F.E.A.R. unit. Armed with hyper-sensitive reflexes, you can slow down time and experience the game's close-quarter battle sequences in vivid detail. You'll need every advantage you can get as you square off against some of the most ferocious A.I. ever seen in a game. F.E.A.R. contains both a single player campaign and multiplayer modes that are available for play through Xbox Live or System Link play.
Initial thoughts on the demo, courtesy of K1lla’s Xbox Domain, are that the graphics are up to par for a high end PC, "but not for a next gen console". Let's hope for a Xbox Live Marketplace demo shortly.