The Back Area is a medium-sized area housing a long hallway with multiple rooms seen on either side of the hallway. The Back Area is typically accessed after entering the doors in the backstage corners of The Theatre.
Inside The Back Area, the zone appears to be abandoned, leaving an untidy mess for players to navigate through. This is presumably the employees-only room of The Supermarket. If the players go down the stairways from either end of the hallway, they will enter the public storage rooms of The Supermarket.
Harvestables that can be found in the area include Bad Dust, Clock, Concentration Cube, Cursed Cards, Dream Dust, Dream Mushroom, Freedom Cube, Jerk Toothpaste, Liquid Maze, Plugstack, and the Textured Teakettle.
Overall, The Back Area serves as a zone to direct players to The Supermarket or The Theatre, depending on the player's position in the Nightmare. Not much can be done in The Back Area, other than being primarily used as a way to access shortcuts to The Road or to challenge the Racing Clown to a race.