Have you discovered vents that require a tiny person? This Stranger Things 3: The Game Where To Find Tiny Person guide will tell you where you can find the tiny person in question so you can use their perfect size to gain access to new areas and secrets via previously inaccessible vents.
The vents work in very much the same way as Hacking and Bolt Cutters. There are certain areas, specific rooms, that are locked away behind a certain activity. However, you don’t need to hack or cut your way into a vent, you simply need someone small.