The Forest is the first location the player encounters in the game Inside. Players are introduced to the Boy, who slides down a hill of rocks at the beginning of the game, in this level. The Forest also acts as the backdrop of the game's title screen upon opening the game.
The Forest features tall, bare trees (most likely Redwoods) spaced out among rocky inclines and steep cliffs. A hazy fog filters through the air, making it hard to identify objects in the background. Small streams, ponds, and cliffs occasionally dot the landscape, and man-made roadways and artifacts span the Forest as well.
One of the Forest's most distinguishing features includes cylindrical machinery that seem to be attached to some other device above and out of view via pipes. While the nature or purpose of this machinery is unknown, it can be surmised to be either a power collector (akin to a biomass electric generator) or a collector of something.
At the start of the game, the Boy is seen sliding down a hill of rocks. Upon reaching level ground, the Boy progresses to the right until he witnesses a truck full of people in its trailer drive away. A bit later, the Boy sees two individuals either guarding a cylindrical device or simply discussing something. The individuals close onto the Boy's hiding spot but look away at the last moment and move away, allowing the Boy enough time to dash to the right.
Further down the path, the Boy comes across a tall wall where he must use a dilapidated refrigerator to hop to the road on the other side. The truck with its trailer is seen once more on the road, this time accompanied by another individual and a guard dog. Crossing the road and proceeding further down the hill, the Boy eventually jumps into a shallow river. In the distance, more guards use their flashlights and spot the Boy crossing the river; they release their guard dog which chases after the Boy until he jumps a wide gap, preventing the dog from following the Boy.
Climbing the vine-encrusted ledge on the other side of the gap, the Boy runs down the path as a truck drives down a parallel road in the background. The Boy hides behind some rocks and avoids the car's spotlight successfully; however, the Boy has to run past the headlights of the same truck and the guards spot him this time. One of the guards chases after the Boy, but he trips on a piece of log and gives the Boy enough time to hide behind an abandoned trailer-like vehicle as the truck passes by once more. The Boy evades the headlights of the truck and jumps down a tall outcropping while the guards shoot at the Boy. Unable to follow him, the guards send their dogs to chase the Boy. Without options, the Boy jumps down the cliff and dives into a small, deep river, successfully ending the chase for the moment.