Deliberate mistake: The same shot of the railway station concourse is used when Graham and George are heading to work, and also when George commits suicide. The giveaway is that several people are seen in the same position. (00:05:00 - 01:20:30)
Continuity mistake: When Graham is trying to electrocute his wife, he leaves the end of the black sticky tape on the opposite side of the bulb to the chain. When his wife tries to put the electricity back on, it's moved half way round the bulb. (00:30:00)
Revealing mistake: When Graham and Stella are in bed, the camera shows only their arms intertwined as if he's lying on top of her. She's gasping loudly in response to his thrusting, but their arms never move back and forth to reflect this, so it's clear they're not really having sex.
