Continuity mistake: In the exterior shot of Sal entering the bank, there is a car parked by the door. In the interior shot, the car is not visible behind Sal. This mistake is reversed half a minute later when Sonny enters the bank. There is no car in the exterior shot, but it can be seen in the interior one. (00:04:00)
Dog Day Afternoon (1975)
Ending / spoiler
Directed by: Sidney Lumet
Starring: Al Pacino, Carol Kane, John Cazale, Penelope Allen, Beulah Garrick, Sully Boyar
Sal and the hostages are taken to the airport in a car and as there about to go to the plane, the driver gets a hidden gun, shoots Sal in the head and Sonny is arrested. All the hostages are free and Sal is lead off on a gurney while the police read Sonny his rights. Sonny goes to federal prison for 20 years. Leon gets the sex change operation. Angela (Sonny's wife) and her children live on welfare.
Kruger-Brent
More mistakes in Dog Day Afternoon
Leon: I mean, how do they expect you to get uncrazy if you're asleep all the time?
Answer: He didn't. He just assumed the cops would try something like that, substituting a cop for the real driver. What he didn't anticpate is that they had substituted cops for everyone around the bus when it arrived, and when he replaced the black driver he would have to (unknowingly) pick a cop, regardless. Incidentally, this part of the story is completely factual, it actually happened that way.