I was thinking about how be get to hard to reach places in the game, and I came up with this idea. Maybe we could use the duct work in the store to get to places that are otherwise blocked off. It would be much like traveling back and forth between the dark world and light world in The Legend of Zelda: A Link to the Past, where Link has to go between worlds due to slight differences that allow him to bypass obstacles. Our character could have a different set of moves or abilities in the ducts. Maybe he would have to rely on a flashlight to see anything. Maybe he has to avoid certain areas that could blow him around or suck him down some shaft. We could also have weak spots in the ducts where we might fall through. The enemies could consist of rodents and spiders that have been mutated by failed experiments in the research lab. It could be lots of fun. Kind of like a maze. We could introduce this ability in Act 2 where our hero could face some boss and gain a flashlight and access to the ducts upon defeating that boss.
The Every-Mart Duct Work