Amazing experience! The suffocating feeling of a closed space and mounting anxiety, amplified by the oxygen level constantly going down... It is a very atmospheric experience. Loved the puzzle too. I wasn't sure what the fault tolerance for the winning condition was and was so happy that 11m off the spot was accepted! Only after that could I finally exhale in relief!
I also appreciated the little details: books as buttons or the sign "made for Thinky Games jam"! I think the instructions on the wall were a nice touch as well. I didn't notice them right away but the space is small so I saw them very soon. Combined with the game description it gave me a clear picture of the objective of the game.
Would be curious to hear if you plan on expanding the prototype to the full game? If so, what would be the strategy for scaling the core mechanics? Different levels with increasing complexity by adding more moving parts? Or expanding the narrative?
Another question is how to keep the pressure on players as every new won level will probably make them feel more confident.