From Aspyr Media:
Revisiting Wolfenstein 3D, this demo puts you in the capable shoes of B.J. Blazkowicz, a highly decorated Army Ranger who must escape Castle Wolfenstein only to return in an attempt to thwart the evil experiments of Heinrich Himmler, a Nazi scientist. Make your way through German villages overrun by the occult, hidden crypts, forests, air bases, weapons facilities, genetic labs, and other deadly locations. Encounter German soldiers and other more mysterious foes, and use a variety of weapons to defeat them.
This demo lets you play two levels of the first mission, in which you escape from the infamous Castle and then fight your way through the crypts on your way to discovering a dark secret.
Notes: This is a large file (106MB) and may take several hours to download via modem.