Halloween Horror Nights IV continued the trend of getting bigger and bladder every year. The event was expanded to seven nights and featured four haunted mazes. These included the returns of Dungeon of Terror and The Psycho Path maze, as well as two new houses The Boneyard and Hells Kitchen. HHN 4 also introduced two features that would become synonymous with Halloween Horror Nights: the first scarezone and the Chainsaw Drill Team. The scarezone was created to centralize the scareactors to create better scares while in a safer environment. The term scare-actors was coined for the first time.
This year also marked the last time Robosaurus would appear at the event for twelve years.