Booo!

You are attending the great ghost apprentice competition in "Blackrock Castle" in northern Scotland. In this tournament, you have to scare as many visitors as possible in order to win the disputed "Ghost Master" title. Who is going to be the fastest ghost? In Booo!, you want to take the corridors and the secret passages, pass through the walls, and change colors to find the right path and scare Blackrock Castle's visitors before anyone else.