Because of problems with the Writers Guild of America, Terry Gilliam and Tony Grisoni were not able to credit themselves as writers of the screenplay, despite the many changes they made to Ehren Kruger's original script. They invented a credit for themselves as "Dress Pattern Makers" and were quoted as saying that the film was made from a "dress pattern," not necessarily made a "screenplay."
The glass slippers are from Charles Perrault's original French version of Cinderella. (In fact they were fur slippers, later changed to glass by a typo because the words are very similar in French.) In the Grimm adaptation, she wears gold slippers.
In June 2004, Bob Weinstein and Terry Gilliam reached a stalemate over the final cut. Gilliam decided to place the film on hold for six months. He made Tideland (2005), then finished this feature in January 2005.
In 2013 German singer Markus Grimm, one of the descendants of the real Brothers Grimm, said in an interview to the German magazine "Stern", that he thinks this movie is great, even if it is historically completely out of it.
The trivia items below may give away important plot points.
The Mirror Queen using the blood of young girls to restore her youth is based on the legend surrounding Transylvania's Countess Erszebet Bathory, one of the first serial killers, in the early 17th century.
The most expensive scene in the movie was cut because it occurred early in the story, and nothing would've been able to top it. In the brothers' first trip in the forest with Angelika, The party is attacked by a tree, which grabs Angelika with a branch and swings her up in the air. The scene's special effects were almost completed before it was cut. It's available on the DVD's Special Features.
Many references to fairy tales (most recorded by the Grimms) are slightly different from the actual tales. Little Red Riding Hood is referenced only by her red cape, the heroic woodsman is an evil henchman, and the Big Bad Wolf is a large wolf instead of a diabolical personification. Rapunzel is an evil queen who locks herself in a tower to escape a plague. The Gingerbread Man is an incarnation of a mud monster. "Hans" and "Greta" are the original forms of the diminutives "Hänsel and Gretel" ("little Hans and little Greta"). Cinderella is really the Grimm Brothers as they scrub the floors (the deleted scene on the DVD makes it clear). The evil queen is also the queen from Snow White. In the scene with the mill witch, the brothers tell the farmer that their swords and shields were forged by prince charming who awoke briar rose (Sleeping beauty's name while she is in hiding), and all the girls' fingers are pricked as they fall into a deep sleep. The Woodsman places slippers (which turn to glass) on Sasha's feet as he prepares her for the crypt. Jack from Jack and The Beanstalk becomes Jake and tells everyone a story of an imp whose name they had to guess, a clear reference to Rumpelstiltskin. The bed the Mirror Queen sleeps on is a reference to the Princess and the Pea.
Matt Damon was strung up by his waist for the torture chamber scene. He could only stay up for 90 seconds at a time because the rope was crushing his ribs, cutting off his air supply. Terry Gilliam had a prosthetic made for him, but the studio didn't want the actor to wear it.
Sleeping Beauty is referenced by the girls having their fingers pricked, and by the brothers telling the farmer that their swords and shields were forged by Prince Charming who awoke Briar Rose (Sleeping Beauty's name while she is in hiding).