Secret Neighbor is a worthy branch of the mainline story. It lets you experience a bunch of brand new gameplay features and even play the Neighbor himself! Is it scary? Well, waiting for the enemy to jump from the next corner is really nervous, and you can even scream from an unexpected turn.
The game keeps you in a constant hurry so that you cannot hide or ambush like the Neighbor. Run as fast as you can to survive and solve the quests!