The 3D graphics and sound are at the very least serviceable. Like the first Ultima Underworld (another great great from the same time period) there is much to explore in multiple levels and each level is often quite different from the others. There is spooky lighting and a great atmosphere as you excplore rooms and corridors.
Unlike most games, the story is uniformly excellent and often genuinely surprising in its twists and turns. Easily one of the best PC games of its time in any genre.
Origin published this game and didn't seem to know what to do with it. It didn't sell very well unfortunately either.
Truly deserving of the title -- "Classic PC Game"