In the 'building-block bridge' demonstration for John Thomas, Harley places a red block on top which becomes blue in the subsequent wider shot.
The yellow boom/bucket truck that begins at Radio City Music Hall and Times Square changes to a completely different truck when it arrives at the clinic.
The symbols the "doctor" draws on the wall for John Thomas change from when first drawn to the following shot.
Fettucini's name is spelled correctly in the end credits, but misspelled as "Fetucini" on his business card.
The supposed fixed infrared camera in John Thomas' room at the clinic moves, and shots from different angles are shown when played back the next day - and they are in color.
Although the film is set in New York, it was largely shot in England, and most of the supporting actors are not only British but make no attempt to hide their accents.