Eternal Darkness is a mature third person horror adventure. There are twelve playable characters, each from a different period of time spanning many centuries. Depending on the time period you will be given a wide variety of historically accurate weaponry, from swords to guns to crossbows and many others. The game also employes a magic system. You cast magical spells using Runes, which can be found in the game. These spells not only aid you in combat situations, but they can help with exploration and puzzle solving too. One of the more unique offerings in Eternal Darkness is the Sanity meter. Don't let this meter drop too low. You will begin to have scary and often disturbing hallucinations. Not only will these hallucinations shock you, they will also affect the game. You might lose runes or health after hallucinating for example.

Players that pick up this oft forgotten Gamecube gem will be treated to a lengthy adventure, about 20 hours or more. The incentive to replay the game is high, there are three branching paths that you can choose to take. Besides changing the ending of the story, you will face different obstacles, puzzles, and monsters. Those players that take the time to complete all three paths will be treated with an extra special ending.