The dungeon is randomly generated as you move through it, such that no two games will be the same. Thanks to this, The Unknown is a very replayable title that always (or almost always) will have a fright awaiting you.
You'll find many elements typical of horror games in the various corridors and rooms of the catacombs, such as traces of blood, locked gates, or objects that fall in your path. But what you will really be afraid of is 'the creature', to give a name to whatever is that's in there with you.
This ghostly creature will follow you everywhere and, occasionally, attack your mental state. If it manages to send your fear level over 10, your character will go completely insane and you lose the game.
The Unknown is a first-person horror game in the same vain as Slender, but offering a slightly different experience. It also has spectacular graphics ... though perhaps a little too dark.