Nuclearstein is a mod for registered Wolfenstein, made by Marty Beltran. It was released on July 11, 1999.
The mod features 11 new levels, played on the first two episodes. In the first episode, 9 levels are playable, with the second episode having only two genuinely new levels. Others were based on the original Wolfenstein levels.
Graphical changes include material taken from the Lost Episodes along with some new textures, including a pelican and a regurgitating frog. Furthermore, the pelican or an offshoot thereof, a tiny bird with a large beak, features as a piece of treasure.
The mod is playable in SDL as only map files and the VSWAP followed the download. No Read Me was attached.