Overall everything is pretty solid besides some issues with clicking on/placing objects. There needs to be some prep time allowed for solo players, basically impossible to play alone. If possible, kitchen should scale based on the lobby size. Part of the main problem playing solo is the travel distance to run to every corner of the kitchen. The fridge is just placed way too far and only being able to grab one object at a time makes every action take that much longer. I think a Hotbar/inventory system could ease a lot of problems.
Also, a glowing ring on the customer table of where to place the tray would be nice.
Other than that, with some love and care I can see myself having fun with this.