Level 80 is an unnamed and unused level that was cut from Dungeon Keeper. It is in the 21 May 1997 and 28 May 1997 prototypes.
The player starts with five Imps, three Orcs, and two Horned Reapers, all of whom are level 10, and a Prison and a Torture Chamber. For whatever reason, there is also a single Torture Chamber tile some distance from Red's starting dungeon.
The only script is the spawning of a bunch of level 4 Mountain Dwarves (who, curiously, are in a party named 'TWO'), who will of course be quickly pulverised by your Orcs and Horned Reapers. It seems that this level was meant to test capturing and converting Mountain Dwarves.
The final game has another level at level 80. The Deeper Dungeons and Dungeon Keeper Gold have Morkardar at level 80.