According to the ESRB, this game contains: Blood and Gore, Violence
Parents should be aware that Eternal Darkness features large amounts of blood and gore, dismemberment, graphic violence, and a significant amount of occult themes throughout the game. There is no sexual content, and very little to be concerned with in the way of profanity. Its definitely not for the little ones.
Gamers in general will get a mixed bag. The game features a very interesting plot held back by simplistic and repetitive elements. It's basically a good, solid game, but some people may be turned off by the one-note gameplay.
Silicon Knights fans will enjoy the trademark high-quality voiceovers and complex story elements that made the developers so popular in the first place. Eternal Darkness may not be the blockbuster it was made out to be, but it's a solid game and a good return to form.
Survival horror fans won't get the same formula they may be used to. Eternal Darkness fixes many problems that plague the genre, but the tone and mood are different enough that I wouldn't call it survival horror. Still, if you like creepy stuff, its definitely worth a look.
Hearing Impaired gamers have the option of viewing full text during all dialogue and cutscenes. However, one puzzle late in the game can only be solved by auditory clues. If you don't have an FAQ with some very detailed information, this may be a problem.