During the end credits, all the actors turn up as Circus Performers and are introduced by the Ring Master - ending with Bud Cort, who lies dead in the center ring.
The opening credits are done twice. The credits are superimposed over Daphne Heap (Margaret Hamilton) rehearsing "The Star-Spangled Banner" with a marching band in the Astrodome. She stops the song and accuses the band of being on the wrong key. The band begins again, and the credits also start over, with the same titles repeated with the "better" version of the song. One of the opening credits reads: "Title song by Francis Scott Key"
Introducing Shelley Duvall
Also during the circus finale when the cast is being introduced by the ringmaster, you can see some cast credits on the Houston Astrodome's scoreboard.
Instead of a roar, when the MGM lion opens his mouth, Rene Auberjonois' voice is heard saying "I forgot the opening line".