Bunker Assault is a mod for registered Wolfenstein 3D, made by Pedro Lopes, João Lopes and Luis Lorenco Lopes, who are all brothers - presumably. The mod was released in December 1994.
The mod brings 10 new levels and a modified VSWAP to the mix, including some rather nasty stuff, although most of it is hidden in the files. Be prepared.
For many years, the set fluctuated as Bunker11. In terms of design it holds up pretty well for its age.