Dream Chefs is a time-management cooking game: orders arrive, dishes have to be prepared through their steps, and customers won't wait forever. The challenge is running several dishes in parallel rather than any one being difficult.
Money from served orders buys equipment upgrades, which is what makes the later, busier stages possible.
Parallelise. Start the longest-cooking dish immediately, prepare fast items while it's cooking, and always serve whoever is closest to leaving rather than whoever ordered first.
Yes — the later stages are balanced around an upgraded kitchen, so investing between levels is part of the progression.
Yes — a light browser game with nothing to install.