For me it's how you discover one by one elements of the history of the "aliens" and how you use the physics to solve some puzzles. I also love the story. IMHO i

For me it's how you discover one by one elements of the history of the "aliens" and how you use the physics to solve some puzzles. I also love the story. IMHO is one of the best videogames ever made together with Obra Dinn