I am a fan of Mental checkpoint and watched the video after playing. I would love to see a fleshed out version as there's a lot of good ideas.
I would mention issues, but you've covered most of them in your video, but here's a couple thoughts.
Another interaction you may have missed is using Sentience as a double jump, as you can stand on it and lift yourself off the ground, then jump.
In terms of puzzle design, I would like to see levels that need more than 1 ability to solve. I think the design space is there to be explored, but understably not explored fully for 48h.
Once again mhch love to Mental Checkpoint. Was a lovely surprise to see a gmtk jam from you, and I enjoyed seeing the development process.