### Sources: en.wikipedia.org/wiki/Batman_Returns; www.imdb.com/title/tt0103776/trivia?ref_=tt_trv_trv ###
1. Neither Tim Burton nor Michael Keaton had been signed up in advance for a sequel; Burton came on board only after the script met all his demands (he hadn't been entirely happy with the first Batman's screenplay), whilst Keaton only agreed to do the second film after a serious hike in salary.
2. It was intended that the character of Robin be introduced in the sequel to Batman. Reportedly, Tim Burton collaborated with DC Comics artist Norm Breyfogle to redesign the Robin costume so that it would coincide with the one planned for the film. Kenner Toys even went so far as to produce a corresponding action figure, but when Robin was eventually written out of the script, Kenner released the toy anyway, as the character newly rendered in the comic books.
3. WILHELM SCREAM: Before Batman straps the dynamite to the strongman, he hurls a goon over a bridge. As the goon flies through the air, he screams the famous Wilhelm scream.
4. Michael Keaton was alleged to have earned $11 million for reprising his role as the Caped Crusader.
5. The final Christmas ball scene is quite symbolic: since it is a masque party all the guests are in disguise. The only two guests there who actually aren't wearing masks are Bruce Wayne and Selina Kyle. This implies that their real personalities are Batman and Catwoman respectively, and that their public appearance without a costume is just a disguise for the society.