The box office receipts were less than expected, so writer George Lucas continued Willow's story in books rather than in movie sequels. The three books are collectively known as "The Chronicles of the Shadow War" and share a writers credit for Chris Claremont and Lucas. They are: "Shadow Moon" (1995), "Shadow Dawn" (1996) and "Shadow Star" (2000)
The earlier drafts of the screenplay contained more background information on the characters Madmartigan and Sorsha. Madmartigan was originally a knight of the kingdom of Galladorn (the kingdom that General Kael mentions having destroyed to Queen Bavmorda) and that the character Airk was the only real friend he had, but Madmartigan's recklessness got him into trouble, as did his love affair with an Eastern beauty that tainted the family name. Madmartigan had a chance to regain his honor in battle, but he ruined the chance by deserting; this explained some of the bitter antagonism between Madmartigan and Airk. Sorsha was originally the daughter of the king of Tir Asleen, who was a good man (he is in fact the regal old man seen at the end after the fall of Bavmorda and Tir Asleen is restored, and can be briefly seen in stone), which suggested that Sorsha had the capability to be good; during the battle at Tir Asleen between Bavmorda's troops, Madmartigan, and the monster, Sorsha encountered her father and he struggled through the stone to ask her for help, which prompted Sorsha to switch alliances from her evil mother to the good side. All of this was lost in the final film but does appear in the novelization as well as the comic book mini-series by Marvel.
As Val Kilmer was getting out of his crow cage between takes, the chain snapped and the cage came down on his foot. His resulting limp is evident during the scene in which Madmartigan and Willow arrive opposite Fin Raziel's island.
Word from Ron Howard is that part of the two-headed dragon "Eborsisk" was modeled after Clint Howard, his brother. He stated that since Clint has had many cameo appearances in his films, and Ron couldn't find a part for him in this one, he modeled the dragon after him.
According to the press kits and subsequent novels, the two-headed dragon was named "Eborsisk", a reference to the movie critics Gene Siskel and Roger Ebert. The word does not occur in the film but made it into some reviews.
A 13lb animatronics baby capable of moving its head and opening its mouth was used for the action scenes. This baby weighed more then the actual baby. And a more flexible prop baby was used in scenes where Willow falls with it.
Willow originally said, "Goodbye, Elora Danan" when handing her over to Madmartigan. During editing, it was realized Willow wouldn't have known her name yet, and so it was redubbed, "Goodbye, little one."
During the close-up shots of the scene where Madmartigan and the soldier are being dragged behind the wagon, Val Kilmer was kneeling on a pedestal behind the wagon, while his stunt double was dragged behind letting the stunt man's legs take the beating.
David Steinberg, the actor playing Meegosh, slammed into the side of an ice rink while ice-skating during production and cut his eyebrow open. The stitches were concealed with makeup for the scene where Meegosh makes his departure for home.
The Chinese government refused George Lucas the chance for a brief location shoot. He then sent a group of photographers to South China to photograph specific scenery, which was then used for background blue screen footage.
Because of slow production during filming, the babies outgrew the props and the baby carrier that Willow had on his back, so they needed a new baby quickly and the second assistant director, Gerry Toomey, recommended to use his new born niece Rebecca Bearman, although never credited. The scene where the baby is sick on Burglekutt was never written into the script. Willow walked with a limp which made Rebecca travel sick, so when she was lifted up, she threw up over his head, and it was so funny they kept it in the film.
The film synchs up in places with the Pink Floyd album The Wall. Including the baby in the basket being on screen while the baby cries at the beginning of Is There Anybody Out There, and the villages elder moving his fingers while the album is playing a keyboard solo until the old man makes a fist which coincides perfectly with a single drum beat. An interesting way to kill a couple hours.
When Willow first meets Fin Raziel, she is in the form of a brushtail possum. Throughout Willow's failed attempts to change her back into her human form, she subsequently becomes a raven, goat, ostrich, peacock, tortoise, and finally a tiger before Willow succeeds in returning her to her human shape.
The twins who played Baby Elora never acted again. On his blog, Warwick Davis shared a picture in 2007 with a woman named Laura Hopkirk who says that she played the baby for the scenes shot in New Zealand, but she is not credited online.
WILHELM SCREAM: It is heard three times: 1, during the chase scene after the escape from the tavern as the soldier's chariot crashes and he is sent flying, 2, At Tir Asleen, when the Brownies trigger the large spear shooter that hits several soldiers, and 3, In front of Nockmaar Castle as a horseman is cut down by the Army of Galladoorn, three seconds after the Brownies emerge from under a helmet.
Ron Howard was looking to do a fantasy film. He was at Industrial Light & Magic during the post-production phase of Cocoon (1985), when he was first approached by 'George Lucas' (I) (qv to direct. He had previously starred in Lucas' American Graffiti (1973), and Lucas felt that he and Howard shared a symbiotic relationship similar to the one he enjoyed with Steven Spielberg.
Ron Howard nominated Bob Dolman to write the screenplay based on George Lucas' story. Dolman had worked with him on a 1983 television pilot called Little Shots that had not resulted in a series, and Lucas admired Dolman's work on the sitcom WKRP in Cincinnati (1978).
Various major film studios turned down the chance to distribute and co-finance it with Lucasfilm because they believed the fantasy genre was unsuccessful. This was largely due to films such Dragonslayer (1981), Krull (1983), Legend (1985) and Labyrinth (1986).
George Lucas initially visualized shooting the film similar to Star Wars: Episode VI - Return of the Jedi (1983), with studio scenes at Elstree and locations in Northern California, but the idea eventually faded. However, some exteriors were done around Skywalker Ranch and on location at Burney Falls, near Mount Shasta.
There is a continuity error that involves the Magic Acorns Willow was given by the High Aldwin. During an interview with The Empire Podcast, Warwick Davis explained that in a scene near the end of the film, he throws a second acorn and is inexplicably out after having only used two of the three Magic Acorns he had been given earlier in the film. Included in the Blu-ray release is the cut scene, in which Willow uses an acorn (his second) in a boat during a storm and accidentally turns the boat to stone. Davis says that his hair is wet in the next scene that did make it into the original version of the film, but the acorn is never referenced.