Continuity mistake: At the outset of the song "Who will buy?", the price of roses is "four blooms for a penny." Then it suddenly doubles to two for a penny.
Revealing mistake: When we first see Oliver Reed, we see his shadow first on the wall at a ramp to the pub. As his shadow spreads its legs, we then see him spreading his legs a moment later. Shadow puppetry was used by the director to give the audience the impression that he is ominous and foreboding before we ever see the man himself. (00:54:10)firstmagnitude