Evil Genius is considered by many to be the spiritual successor to the masterful Dungeon Keeper series. The game is set in the 1960/70s where you play an evil mastermind determined to take over the world from a hidden island base, in the style of a James Bond parody. The focus on building corridors, rooms, and traps, managing the health and happiness of your mindless minions, and making sure the Forces of Good and Justice and Fluffy Bunnies don't kill your mastermind is very DK-ish.

If you're looking for a Dungeon Keeper clone in every sense, you'd do well to just buy DK2 over at Good Old Games. Evil Genius diverges from the DK formula in that the enemies you face don't have to be killed (and oftentimes shouldn't be). As you start, your Heat level (the measure of how much the world alliances hate you) will be low, and thus the only enemies you will normally face are investigators. If you keep Heat-generating rooms and items (nuclear reactors, control rooms, torture chambers, etc) out of sight, the agents will eventually leave and report back that you are doing nothing wrong, reducing your global Heat level. As your Heat with an alliance increases, more powerful agents (thieves, soldiers, etc) will come, forcing you to deal with them in a more heavy-handed way.

Traps have been given a major overhaul from the DK series as well. There are many different types of traps from the dropping cage trap that sprays gas to reduce an agent's Smarts (to make them forget evidence of your evil plans), to wind machine traps to push agents away from where you don't want them, to the standard Team Fortress 2-style machine gun turrets. You can also link traps together to go off simultaneously, so you can push an agent down a corridor with a wind machine, push them down a corner with another, and finally ending up with the agent landing in a tank full of hungry piranhas. By comboing your traps, you gain extra money.