Spooky theme aside, this game is based on the tried and tested formula of "walk through all tiles but only once". But since this gets boring after a while, new elements are added. For example there are 2 characters at the same time, and they can interact with each other. Thus levels become more complex and challenging. Also the story involves all the characters stuck in limbo because they share a common past, so that's a good way to advance the plot too. All in all the game is playable and fun to watch!
P.S. there is also a prequel you can try out here