In the scene where Caden is talking to Hazel directly after having talked to the doctor after his seizure, there is a dog in a box behind Hazel in her box office. Upon cutting to Caden, and then cutting back, the dog is gone. This is the remnants of the character "Squishy", from the original draft of the script. The almost-dead dog was found by Hazel after driving home from the premiere. She was saddened by Caden denying her, and she finds the dog, run over and bloody on the side of the road. She decides to keep it. This is the only scene where he is present, and his presence is not explained.
When Caden and Hazel are talking about Hazel's relationship with Sammy, in the background, the actress Tammy lights a cigarette. Seconds later, when the scene is shown from a different angle, again Tammy lights the cigarette.
Announcer on the radio at the very beginning says it's 22 September. The newspaper is dated in October, it's Christmas when the sinks smashes his forehead, New Year's on the ride home and March in the ophthalmologist's office. Kaufman afforded his film a dreamlike quality by playing with the representation of time throughout.