Factual error: When Malcolm is talking on the telephone in an extreme close up, you can see the connector on the phone is one of the modern snap-in modular jacks. Telephones in the 1960's did not have those.

Audio problem: In the scene where Malcolm is playing Russian Roulette, watch closely around the part when Malcolm begins to stand over the other guy with the gun pointed at his nose. You can hear Malcolm talking, but his lips aren't moving.