Holy fuck, you've stumbled upon a good game! Let me explain what is going so you can have some idea of what you've been missing.
Dungeon Keeper and its sequel Dungeon Keeper 2 is a strategy micromanagement video game published on the PC for win95 to Vista, but it works fine on wine for the Linux inclined..
Dungeon Keeper 1 was released June 26th 1997, while its sequel was released June 30th 1999. Both games were developed by Bullfrog, the first game being managed and led by Peter Molyneux (remembered for his shit fest of a series Fable).
The game puts you in the position of the unnamed, omnipotent being known as the "Dungeon Keeper". As a dungeon keeper, you're expected to raise up an army of evil minions and help your friend(?) the horned reaper reach the surface world, for him to reign down terror onto the humans that populate those lands.
But wait, there's more! while you're working on your evil fortress of doom the knights, elves, fairies and all those other boring lawful good characters you play in every other fantasy game on the face of the planet will come in to try to kill you. It's your job to take your army of minions, catch all of them you can (kill those who resist) then turn them over to the Dark Mistresses for "reprogramming". With the enemy army now under your control, it's easy to take the overworld for yourself! See? Those pointless elves are good for something after all!
In order to do that, you've got to keep an eye on your gold, your mana, the position of the enemy player, your weak points (unfortified walls), your rooms, what your minions are up to, where to strategically place traps, and more. As a Dungeon Keeper, you're expected to build rooms that will attract certain types of minions (and allow for all sorts of other things, like converting enemy minions or heroes). Rooms cost money, so you'll have to mine yourself a few gold veins to make bank. These veins run out however, so you do have a time restraint even if there isn't one present. However, in some maps, there are gem blocks, which are an infinite source of wealth. This is important if you need time to level up your minions before a big battle.
Dungeon Keeper 3 was in the works, until EA ran over bullfrog and canceled it. Fuck EA.
Dungeon Keeper has inspired Minecraft, Dungeons, A Game of Dwarves, Impire, War for the Overworld and surly more to come.
At the end of the first Dungeon Keeper, the boss battle is with the "Avatar", which is just a straight up sprite rip from the Persona 4's Avatar.
Over 200,000 people have signed the petition for a new Dungeon Keeper, yet EA still shovels out sports games instead of listening to what people want.
War for the Overworld (A kickstarter project made by subteranean games) has been released on steam for bedrock beta testing, it is a spiritual sucessor to the Dungeon Keeper series and is titled after what the third in the series of DK's would have been named,
EA are cunts.