When Tom is talking to Walt, who is in the pool, about flying down to Mexico, the amount of white sunscreen on Walt's lower lip changes between shots.
At the beginning of the movie when the doctor is shot, he falls into the pool. When the pool lights are turned on, there is no trail of blood in the pool. Anyone shot in the chest would show a lot of blood streaming into the water.
Alice tells Tom her dog died on a Saturday. However, the headstone for Ceasar notes the date of death as April 1, 1966, which was a Friday.
Sgt. Valens mistakenly uses Code 9 to mean a "stakeout". The correct one is Code 5.