My game keeps freezing

I've made a endless runner mobile game and when I start it up and no matter what level i pick it works fine.

But when i go back to the menu and pick another level it freezes, also when i go to the menu and go back to the other level game play is still frozen

All the debug.log alerts keep coming up, the fire button still works, the bullets appear (but dont move) and even the menu still works

Here is a video of it: https://youtu.be/QCE2d9zlXlw

Does anyone have any suggestions as to what the problem could be?