# Elemental Planes
The Elemental Planes form the first four levels of what NetHack refers to as the End Game. As the name suggests, each of the four Planes represents one of the four elements:

the Plane of Earth
the Plane of Air
the Plane of Fire
the Plane of Water
The planes always appear in this order, and are followed by the Astral Plane, which many players consider one of "the planes".[1] All of the planes are no-teleport and have undiggable floors.

Contents

1 Accessing the Planes
2 Variants

2.1 SpliceHack

3 References

Accessing the Planes
The Plane of Earth is entered by climbing the upstair on dungeon level 1 with the Amulet of Yendor in your possession. If you do not have the Amulet—perhaps because you have been fooled by a fake—you will instead "escape the dungeon", and the game will end immediately, so beware. A cursed potion of gain level is a foolproof way to test if your Amulet is real, as you will only "feel uneasy" with no effect at all  if you quaff it while holding a fake Amulet. Once you enter the Planes successfully, it is impossible to return to any of the earlier dungeon branches. 
Movement from one plane to the next, and from the Plane of Water to the Astral Plane, then requires finding a magic portal. It is impossible to move backwards to an earlier plane, or to move forward without the real Amulet of Yendor.

Variants
Several variants, such as GruntHack and UnNetHack, present the Elemental Planes in a random order - this makes the End Game less predictable and more challenging.

SpliceHack
SpliceHack adds new endgame levels. The sequence of levels is[2]:

Plane of Earth
Gemstone Array
Plane of Air
Plane of Ice
Plane of Fire
City of Brass
Plane of Water
References

↑ dat/dungeon.def in NetHack 3.6.6, line 134

↑ https://github.com/NullCGT/SpliceHack/blob/Spl-R-1.1.0/dat/dungeon.lua