Hades

With Hades, Ablex continued to walk untrodden paths, creating Korea's first FPS. The aesthetics are very closely oriented on Doom, complete with similar demonic enemies that almost count as plagiarism, although the weapon selection might be a bit more futuristic.

The most unique element in the game is the terrain made of voxel graphics, as the stages alternate between Doom style mazes of narrow corridoors (although they're more loosely designed than id's masterpiece) and open, hilly areas that just serve as combat arenas and offer ample opportunity to restock ammunition.

In many stages it's also possible to find and board hovering vehicles, but they completely break the game, as they can fly over most obstacles, are nearly indestructible and usually have so much ammunition that it might just as well be unlimited.