Interesting take on the concept. It took me a little while to realise that I had to drop people on the trolley itself and not on the lever off to the side.
Keeping timing with the trolley as it rotated was challenging and fun. I'd be interested in seeing a version of this with more mechanics around the type of object you drop and how it could impact the environment or the trolly.
I also had some problems with freezing as you say might happen in the description. Is this caused by spawning a lot of people up front into an object pool? Or some other problem?