While it hasn't aged that well, it hasn't aged terribly either. All the core things that made this game interesting and fun to play are still there today. Interesting usable items, strange puzzles that can often lead you to an early grave, and vicious enemies waiting to club you to death, or burn your corpse to a crisp.
There are three classes you can play in this game, and all have weaponry and stats unique to them. All of them offer a slightly different take on playing through the game, and after trying them all out for the first area or so, you'll quickly choose one as a favorite.
Interesting level design, cool weapons and items, surpise enemy attacks, and fast game play keep this game going strong until the end. If you're looking for an alternative to Doom, or maybe even Quake this would be it. Especially since it has the whole fantasy genre twist to go with it, and a bit better level design and interactivity.
If you can figure out how to get multiplayer going in this game, it is definitly worth it. There's nothing quite as nice as slaughtering tons of demons with a buddy, and having help figuring out puzzles and finding keys strewn through out the well designed levels.
However don't expect to have an easy way to do it. All the methods I could find seemed some what difficult to attempt to set up a game, even with third party programs such as Hamachi, it's a bit difficult to figure it out, and get a game running with a friend. There's probably a guide somewhere out there that will assist you in this, if only playing with friends is a deal breaker for you.
Pick this game up if you enjoy playing old school FPS shooters. This one might suprise you, and keep you playing to the end. If you've played it before, it's definitly worth having on here just to blast through a few levels every once in awhile. If you've never played the game before, give it a try, it's worth a spin if you never got to experience it before.
Avoid the N64 Port AT ALL COSTS. It was terribad.