SLASH (SuperLotsaAddedStuffHack) is a variant of NetHack 3.1.3, later updated to NetHack 3.2.2. It initially combined NetHack-- 3.1.3 with NetHack Plus. The subsequent addition of the Wizard Patch produced SLASH'EM.
Tom Proudfoot, who originally created NetHack-- 3.0.10, released six versions of SLASH:
|1||16 Feb 1996|||
|2||18 Feb 1996|||
|3||26 Feb 1996|||
|4||8 Mar 1996|||
|5||17 Mar 1996|||
|6||30 Mar 1996|||
NetHack 3.2.0 was released on 18 April 1996 and Tom Proudfoot released no more versions of SLASH. Enrico Horn later resumed development, releasing a SLASH based on NetHack 3.2.1 on 8 October 1996. The last version, called SLASH 4.1.2-8, was a merge with NetHack 3.2.2.
Enrico Horn's website has disappeared, but is still visible on the Wayback Machine here. As the DOS source archives found there are unfortunately truncated, interested parties should download the Unix patch instead. This tarball should be unpacked into the top directory of a clean NetHack 3.2.2 source tree; it will unpack into new files and two patches. If only the first patch is applied, the resulting tree is in agreement with the recoverable parts of the DOS archive.
The Wizard Patch proved popular, and in time Warren Cheung ported it to SLASH, calling the resulting game SLASH'EM, the EM part meaning Extended Magic. He released it on 7 January 1998. SLASH and SLASH'EM coexisted for the rest of the 3.2.2 era.