Revealing mistake: When the "dudes" are taking out a load of bin bags, you can see through the lighter coloured ones that they are actually filled with polystyrene chips (the packing kind) rather than any litter.
Revealing mistake: When Chester completes the Rubik's cube and it transforms into the continuum transfunctioner, it descends into his hands but if you look closely, you can see that he takes his hands away from it and it magically floats just above his hands.