Great game! A one time use rag, make sense, it's a fairly simple but fun and theoretically endless game as the rate of customers increase, more upgrades are bought and so on until you have had enough fun, or it becomes unmanageable. The core design of creating a system that's logical and can handle continuous advancement naturally with just tweaking variables like spawn rates and limits are excellently done for a game jam's style.
Organic obstructions by making the tables, waiters and tables have collision is extremely frustrating, but also adds dynamic complexity to the game. Sound design is good too and along with the repetitive, predictable actions of getting a rag, cleaning, returning, ad infinitum, more impactful and satisfying, the breaking of plates is a nice sound that accentuates the task and helps set a flow state along with identical mouse movements throughout the game. It bums me out when they only leave stains and I don't hear the clack clack of plates being swept off the table and shattering on the floor, haha.
Rush hour is well anticipated, use of progress bars is good to convey information simply and quickly, the time dilation of the rush hour definitely makes things much more chaotic, but also makes all the collisions that much more frustrating, but that's intentional.
Great job on the game!