After leaving the guesthouse, Alice says to Ken, "I'd better get ready." In the next shot her hair ribbon suddenly disappears.
In some scenes where Alice writes a diary, she writes in the right side in long shots, but in the left side in close-ups.
Length of candles when Alice is singing "Les Filles de Cadiz."
Ken and Mary Lee come to a poolroom by car and close the car door after getting out. But in later shots it is left open.
Vincent arrives at Alice's home on, according to her diary, August 3. The next day they go for a ride together and Alice writes about it in her diary. The date must be August 4, but her diary indicates (incorrectly) that it is August 5.
Outside of the "Mt. Kisco Playhouse" there are very tall mountains visible in the background but there are no mountains that size around Mt. Kisco, New York or anywhere a relatively short drive or train ride away from New York City.