When Annie drives Alvy home from the tennis game she quickly parks behind a red car. The next cut, showing the two exit the vehicle, clearly shows them parked behind a blue car.
In the final credits, Christopher Walken's name is misspelled, reading as "Christopher Wlaken".
When Annie is driving on the freeway with Alvy, a police cruiser can be seen in the background holding back traffic.
New York State flag on University Of Wisconsin auditorium stage. (Scene was shot at Manhattan's Fashion Institute Of Technology on 7th Avenue.)
Near the end of the film when Annie and Alvy meet outside at the restaurant, the crew is reflected in Annie's glasses throughout the scene.
Given the sound of the roasting pot on the stove, there is no water in it when Alvy drops in one of the (dead) lobsters.
When Annie Hall sings "It Seems Like Old Times," she sings "walk" twice. It should have been:
Seems like old times Having you to walk with Seems like old times Having you to talk with....
A boom microphone is visible in the cabin bedroom scene. This is reportedly deliberate.
After Alvy deals with the spiders at Annie's, Annie says she thought she heard someone else with Alvy when he answered her phone call in the previous scene. He was (with Pam - (Shelley Duvall), so Alvy makes up a lie about having his television on. But Pam was perfectly quiet during Annie's call.
Annie's "thought" subtitle "I dabble? Listen to me. What a jerk" appears before she says she dabbles.