KeeperFX is a fan-made open-source remake and expansion of Bullfrog's 1997 classic Dungeon Keeper. Rather than simply emulating the original game, KeeperFX rebuilds and expands its engine, allowing the game to run properly on modern systems while introducing extensive fixes, new features, improved controls, and a substantial modding framework.

You play as the Dungeon Keeper, an appropriately sinister supernatural entity whose job is to construct an underground fortress, recruit monsters, manage resources, and defend your territory from invading heroes.

The central premise remains one of the game's greatest strengths: you're playing the villain.

Instead of controlling noble knights and saving kingdoms, you're digging rooms into the earth, building training rooms and treasure chambers, imprisoning captured heroes, and creating increasingly unpleasant accommodations for your creatures. Imps dig out new corridors and claim territory, while creatures such as trolls, bile demons, vampires, dragons, and warlocks become part of your growing army.

Your dungeon is also an economic machine. Gold must be mined and stored, creatures need to be kept happy, rooms have specific purposes, and your dungeon's layout affects how effectively everything operates. A poorly designed fortress can become a logistical nightmare just as easily as it can become an impregnable stronghold.

Combat eventually becomes unavoidable. Heroes will invade your territory, and you'll need to position creatures, construct defensive traps, and personally intervene when necessary. KeeperFX retains one of the original game's most memorable mechanics: possessing your own creatures and experiencing the dungeon from their perspective.

The original campaign provides a substantial series of increasingly difficult scenarios, but KeeperFX dramatically expands the experience through custom maps, campaigns, creatures, rooms, spells, traps, scripts, and gameplay modifications.

That's where the project becomes much more than a compatibility layer. KeeperFX has effectively become a platform for continuing to develop Dungeon Keeper itself. Its community has produced an enormous amount of additional content, while the engine provides tools that allow creators to modify the game's behavior at a fundamental level.

The project also addresses many of the technical limitations of the original release. Modern resolutions, widescreen displays, improved controls, bug fixes, enhanced multiplayer functionality, and numerous quality-of-life improvements make the game substantially easier to enjoy on contemporary hardware.

Most importantly, KeeperFX preserves the original game's personality. The humor is still dark, the creatures are still ridiculous, and being an evil dungeon overlord remains considerably more entertaining than it has any right to be.