Continuity mistake: When Bender is strapped to the table at the beginning of the reverse fossilization process, he has sensors on his sides, ears and ankles. During the process he magically gains alligator clips on his fingers and toes and sensors on his wrists. They spontaneously appear when the Professor pulls down the lever to start the process.
Continuity mistake: When the Professor shows that the woo-woo sound was air escaping from human-Bender's rolls of fat, there are small grey bits of debris on the wooden floor of the stage all around him. When the crowd gathers around Bender – seen from above - they are gone.
Continuity mistake: There is a weird case of musical tables going on during the Professor's Nobel Prize presentation. When Professor Wernstrom stands and says 'He needs medical attention.' he is sharing a table with an African-American man (who drops his pipe) and a younger man in a green shirt. On the table is an empty retort, an empty glass, one knife and two plates with half eaten meals on them. When he stands and tells the Professor he isn't going to get the Nobel Prize there are three plates with complete meals, a full retort and a full glass and two sets of cutlery. The African-American man has regained his pipe and is at a different table, and a white, bald man has joined them.
Continuity mistake: Just before human-Bender is given the nachos in the bar, we see a blue table littered with food debris directly behind him. When he starts stuffing himself with the nachos the table is red and the litter is gone. When the crew prevent him from eating nachos and 'going to the bathroom' at the same time, the bar is a wide open space with no tables at all.
Continuity mistake: When Bender and Santa are destroying New New York, we see an outside shot of Planet Express with the Professor's titanium shutters covering the entire building. But when we see everyone huddling on the couch, you can see out all the windows. (00:19:35)
Continuity mistake: When the music starts in the bar human-Bender is stuffing himself with nachos – then he leaps off his stool, grabs a pint glass, a cigar and a handful of nachos and starts dancing. The pint glass and the cigar appear from nowhere – and there is no bar person to serve them (and no time to do it anyway.).
Continuity mistake: When Bender laments that he'll be drifting through space with just a little swag, he takes a gold wristwatch out of the bag and puts it on. The watch disappears a few seconds later when he pulls the little piano out of his chest storage and is never seen again.