Hello there, read your post and played the game for a bit! It feels you are open to critique, so here is mine :)
The idea is great, especially for a game jam. I am not into the level build/design concept personally so I will mostly stick with how the game feels.
Your game requires investing a good chunk of time to actually pull through and enjoy, unfortunately, with so many games, people will not play more that 10 minutes on average per game, and this is an important factor to consider when making a game of a game jam, it took me about 10 minutes to finish a run.
It feels that you overshoot yourselves trying to build the full idea rather than sticking to a shorter version and polishing the rest. Honestly, your game is not my piece of cake and by no means I have a plan or suggest I could do better.
Controls did not feel right, felt inverted and I was constantly finding my mouse outside of the screens bounds. Mid air adjustments did not properly register through resulting in frustration.
Even though it was clearly stated in the intro, it did not stick with me that if I click yes, I am not getting the chance to contribute to a new or existing run, even though I would not spend much time if at all building a level.
When I returned to the main menu, looking for a way to contribute to a level, I entered the Create Level(not for active run) and the free hand text in the level building area really had me close it almost immediately. And this is a shame as the overall UI and appearance was ok, I guess maybe you run out of time.
Wish you the best, if you have the time, you can try our game.
Tip or Trip - 3D Action, Isometric, Physics Based, Waiter Simulator
https://itch.io/jam/brackeys-13/rate/3349761