Just like Limbo, this is a story not told by narrative, but by environmental storytelling. You're running through environments and they take you deeper and deeper into the story.
And yet, the key to the story is in this game's title. Inside What is inside? That is the question the game wants us to answer.
The game is visually stunning, but it is also very dark. The graphical darkness is rooted in the darkness of the world that it portraits. There is no music in this game, only ambient sound that will make you feel uncomfortable. The whole world, it inhabitants and even the boy himself is a awkward and it is made to make you uneasy, and it works.
Just like Limbo, you run from left to right, jump and move things. The controls are very simple and you're met with puzzles along the way. In contrary to Limbo, they've removed all of those instant invisible death traps that you could only avoid by learning, and replaced them by timing based puzzles. I don't know if I like it, but it is quite rare that you need to hurry through the levels, most of the time you can stop and just look and rest.
The puzzles are a perfect balance of forcing you to think but not making it hard so you get stuck. I only got stuck once during my playthrough and I think that is commendable by the developer. The game does a good work teaching you the basics of a puzzle and then extending it in the next iteration, so when you get stuck you need to think back of what the game previously taught you, and you will soon find the solution.
This might be the best game I've played in 2016. I truly recommend it for anyone, especially if you liked Limbo. It took me about 3 hours to play through and it was an all in all enjoyable experience.