Terry's necklace disappears and re-appears during her final dance.
The song "Angel of the Morning" was made famous by Merrilee Rush in 1968...the story is set in 1965.
At about 1hr 10 mins, Terry's phone dial shows the 904 area code, but that area code serves Florida, not New York City.
At and hour and one minute into the movie, William Shakespeare's name is spelled Shakeapeare on the Hamlet poster on the wall.
Terry's phone appears to have a modular jack, which had not yet been introduced in 1965.
In "Rosemary's Baby", the character of Terry says she is 'staying with the Castavets' and after her suicide, it is again reiterated she was living with the Castavets. Yet in this film, it is shown that Terry is living on her own in a separate apartment on the 7th floor (7G) and not with the Castavets (7A).
It's not unusual for a professional dancer to injure themself without becoming the talk of the town-having one serious fall is hardly going to brand someone "the girl who fell," especially not in a city the size of New York, where dance hopefuls are a dime a dozen.