I believe that's a good addition to the game. The situations with the iconic villain - now in different environments - and the ending make this DLC worth your time. Plus, since the game takes place moments close to the main campaign, the atmosphere of the game as a whole gets even bigger naturally.
«That ending!»
From a gameplay/story perspective, this is a fantastic piece of DLC for the Litttle Nightmares universe. Unfortunately, the animations often breaking, the AI will staring at/running into walls instead of following you, and various other problems; all make it a bit of a tedium to complete.
«Buggy as hell»