Astrostein is a mod for registered Wolfenstein, made by Bruce Ryder. It was released on October 2, 1996.
The mod features 3 new levels, all found on Episode 1. The overall theme is set in space, and uses futuristic graphics with not many original Wolfenstein 3D graphics being present.
This was based off of the original Mac scenario, which was created by Laz Rojas for WolfAddict Software, but was unfortunately never completed.
The mod can be played in SDL as it only contains new maps and the VSWAP file.
Download Astrostein at The Wolfenstein 3D Vault