Thank you for you feedback! This is our first real jam, so every piece of constructive criticism really helps.
A lot of the issues you pointed out really have to do with us running out of time to finetune the mechanics.
I'll try to answer your questions in order:
-Why you are throwing the sushi: the game is set in an All You Can Eat restaurant, so if you order more food than you can consume, you have to pay an additional fee for each piece that you haven't eaten. Originally, having food left on your plates would mean losing the game. We had to change that because there was no more time to implement it. We will try to make the context more clear with future updates.
-How to throw sushi: we added instructions in the game project's description, in later updates we will add them as you start the game as well. Thank you for the suggestion about the tap/swipe, I agree that it would work a lot better than what we have now! Having the customers react to the food (and even eat it happily) was in our plans, but we were running short on time.
Again, thank you a lot for your contribution!
With a bunch of fixes, let's hope it really does become an addictive casual game! :D