I was anticipating something huge from Eternal Darkness, and minus a few minor things, that's what I got. The atmosphere in this game is absolutely great. The sound especially helps create a nice and moody experience while you're locating and playing through the different levels. If you have the ability to get sucked into games, expect a nice experience from this one.
The game is fun to play. I personally regard the story as one of the finest for a video game, if you have the patience to sit down and understand it. There is many small details in the story that will affect game play for some people, so be sure to understand the story if you pick up the title.
My biggest gripe with Eternal Darkness is the replay value. There are 3 different paths in the game, but they are very similar. Maybe the second time will be okay if you missed any details, but it eventually gets a little old the third time through. Overall it's a good game though, and I am puzzles why it didn't sell more copies.