You kinda get stuck at the bottom because there are no more items I was scared to fall and die without being able to go up again ! That's really hard game I think haha you have yo get used to the physics. Well done
If you could quicly work on speed & visibility. When you play either you are too slow and struggling to get speed or you are to speedy to quicly and you can't control anything.
For the problem of being to slow you could for example add arrow keys control which would let you add force on the left and right to let you balance a gain speed.
You could add a limit maximum of speed (or make it less important if you already did it)
But you know I had a great time with the game it's just a bit hard for me but if you play often you get used to the mechanics it will be good to have this high speed