INSIDE is a platform adventure game that takes place in a 2.5-dimensional world. The boy, controlled by the player, is the main character. The world is divided into various locations, including a farm, a forest, and a fictional laboratory.

As the boy, you need to collect various items, including a weapon, a siren-like creature, and other equipment. The siren-like creature will give you special equipment, such as a special helmet to control bodies, and a variety of other items. In addition, you need to solve puzzles. By the time you finish the puzzles, you will gain more equipment, which will help you on your journey.

In order to complete the puzzles, you need to find out who is who and what is what in the world. You need to find the truth and survive.