The last boss in the dark has a lot of units you might have missed; set your contrast and brightness to pretty much blinding and you'll see those units. hope it helps, it's a luck fest.
I would love to know approximately how much each item improves the waiting/sauce/meat score. If they're all equal, should I fill my lobby with small tables, so I can get lots of them in there? Is the $500 arcade machine better than the $400 one? Without knowing, I tend to choose quantity over quality.