0:28 Goof: When Eric, Alice and Tommy pull up their desk lids it's supposed to say "Eat" but they forgot to put the "Eat" letters in the bottom of the Desk Lids!
The tray for the cake is suspiciously thick, meaning that Bruce pushes the cake into the tray. You can actually see him push the cake down at a little after 2:24 if you pay close attention. The cake itself might be foam, and the outside looks like fabric. You can see crease lines at certain angels. This might make it easier to push down.