I really like the concept. I like the simplicity of it, a very small and limited ruleset that allows for crazy combinations and deep puzzles. It's unfortunate that the game is not quite finished. The thing that's missing the most in the current state is QoL features: moving objects after placement in edit mode, things like that. Also, at first it's not clear what to do, and object naming is inconsistent between pre-made levels and editor. At first I thought "launch" button was to start simulation, turns out it's the name of "ejector" block. I think all block-placement buttons must be visually grouped and separated to distinct it from simulation-controlling buttons (in pre-made mode).
What I disliked a lot is that you have to build from starting loop: you can't place loops mid-air in pre-made mode, and you can't place connectors mid-air in any mode. This makes impossible the approach of "place ejector here to launch there, then build loop way to it". Instead I have to build the entire way and hope I end up in the right place, or rebuild it all again, one block at a time. If I could place objects anywhere (mid-air connectors can be just disabled but shown), and was allowed to move placed objects - this would make the game so much more approachable. Right now, the absence of QoL is what gatekeeps players from fun.
I really like that you implemented level sharing in a veeery approachable way - just by exchanging pieces of text with ctrl-c ctrl-v, that's actually super great. Also I must note that sometimes physics is inconsistent, same level may play differently when person grabs the loop or flies past at high speeds.
Overall it's a good game with great potential. Good job, I am pleasantly impressed!