Fear.
And again .- find out if you can overcome your fear and enter a house that is teeming with infernal creatures;- fight with terrible monsters, creatures of hell or hide from them;- Uncover a secret of the missing relative and understand what is really going on in this place;- Look for secret passages in the walls of the house and the keys to the secret doors, find notes;- and finally, you have to look into the deepest corners of the mind of the main character, to understand who he really is.