There are 21 achievements tracked for dNetHack SLEX in the Junethack tournament.
ascended
entered Astral Plane
entered Elemental Planes
obtained the Amulet of Yendor
performed the Invocation Ritual
obtained the Book of the Dead
obtained the Candelabrum of Invocation
entered Gehennom
defeated Medusa
obtained the Bell of Opening
obtained the luckstone from the Mines
obtained the Sokoban Prize
escaped in celestial disgrace
That was the easy one (obtained at least one alignment key)
Through the gates of Gehennom (obtained at least three alignment keys)
Those were for replay value... (obtained all nine alignment keys)
No budget for bribes (killed Asmodeus)
Postulate Proven (killed Demogorgon, thereby proving the Lord British Postulate (if it has stats, we can kill it))
King of dNethack: Ascend a game with all the new races/roles in dNethack
Prince of dNethack: Ascend a game with half the new races/roles in dNethack
dNethack Tour: Played a game (at least 1000 turns) with all the shiny new races/roles in dNethack