Dungeon Keeper takes real-time strategy into a fantasy setting. You command a dungeon and its hellish minions, and must take them to glory against the hated good guys. You must use your gold to build a fortress and weapons to attack.
The whole thing is a wrap-up of the DOS release with Official NoCD, DOSBOX, and other minor changes, to make it playable under XP and newer. Not the best render possible, but still a huge step forward, because other testers reported playability as "garbage".