One of the best character action games disguised as an FPS you can find. The game has a rough learning curve initially and the lack of ammo can be pretty frustrating for the uninitiated, but it has so many more solid gameplay mechanics to encourage weapon swapping and really engaging with the mechanics. I could be biased, mind, because I have only played on nightmare, so I can't speak if this all rings true for earlier difficulties.

Longtime fans of DOOM might be sad at the turn away from more labyrinth level design in favor of an arena fighter, but I think it created a perfect match.