This game is good. If you are looking for something a little different from the normal Survival Horror games, check this out.
The story is one influenced greatly by the writings of Lovecraft, and especially the Cthulu Mythos that Lovecraft invented. Ancients (Elder Gods) vying for control of the Earth through the means of thier minions. The tale is told through the book known as the Tome of Eternal Darkness (basically the Necrinomicon), and through reading this book, you gain secrets and powers (learn the Mythos).
The most notable feature of this game is the Sanity Meter. The more it drops, the more wierd things start happening. In fact, I still haven't seen all of them.
Graphically this game is both impressive and dissapointing.
The enemies are nicely detailed, and are different looking depending on their alignment. The level designs are very well done, and well detailed. Spell effects and weapon movement/effects are impressive.
The character models for the playable character, however, aren't as impressive. They move realistically, and have a moderate amount of detail (you can see Alexandra's collar bone in close ups of her, for example)...but some of the polygons on them are very odd. In the case of heads meeting necks, it is a bit obvious that they could have done more with the shading and details of each character. While many other areas of the game ar very polished, the playable character models seem to be changed very little from the N64 version of this game (it was originally supposed to appear there, but was moved to the GC).
The sound is simply stunning. Surround sound, excellent sound effects, voice acting, etc. all show a very polished sound design. It's one of the best features of the game.
The story is a bit linear...in order to progress through the game you have to use a skill learned in the previous chapter, starting from the third chapter on. But you can go through the game in 3 different branches, although the story itself is not changed greatly by going down different paths (the end is the only real difference, besides the different alignment monsters). In order to get the full ending, however, you must complete the game using all three paths on one save file.
One nice thing to note is the fact that all of the FMV, and some in game engine cut scenes, are changed depending on which path you take. The changes in the cut scenes is normally just items, or colors of things, but a few are completely different (Paul Luther's, for example, is completely different in the end of it if you use green as opposed to blue or red). The FMV, however, is changed entirely, including dialogue.
It's also a bit short. I beat it in 13 hours the first time through, and then about 8 hours each for my second and third time through. IE around 30 hours of game play, but since you are forced through the game 3 times to get that 30 hours, that's a bit decieving.
All in all a good game. I enjoyed it, and even though it is short, don't regret buying it. Playing through again with a low sanity is something I plan on doing soon.