Back to the Future Part II is a 1989 American science fiction film directed by Robert Zemeckis from a screenplay by Bob Gale; both wrote the story.

It follows Marty McFly (Fox) and his friend Doctor Emmett "Doc" Brown (Lloyd) as they travel from 1985 to 2015 to prevent the former's son from tarnishing their family's future.

When their arch-nemesis Biff Tannen (Wilson) steals the DeLorean time machine and uses it to alter history for his benefit, the duo must return to 1955 to set things right.

Doc explains that their son Marty Jr. will be arrested for participating in a robbery with Biff's grandson Griff, leading to a chain of events that destroys the McFly family.

A Western Union courier arrives immediately after and delivers a letter to Marty; it is from Doc, who tells him that the lightning strike transported him 70 years in the past to 1885.

James Tolkan reprises his role as Mr. Strickland, as do Billy Zane, Casey Siemaszko and J. J. Cohen as Biff's cronies Match, 3-D and Skinhead.

Griff's gang in 2015 includes Ricky Dean Logan as Data, Darlene Vogel as Spike and Jason Scott Lee as Whitey.

Neil Ross provides the voiceover for the Biff Tannen museum while George Buck Flower reprises his role as Red the Bum.

Charles Fleischer plays Terry, who in 2015 indirectly gives Marty the idea to use time travel to bet on sports, and in 1955 is Biff's mechanic.

Director Robert Zemeckis said that initially, a sequel was not planned for the first film, but its huge box office success led to the conception of a second installment.

While most of the original cast agreed to return, a major stumbling block arose when negotiating Crispin Glover's fee for reprising the role of George McFly.

Production designer Rick Carter wanted to create a very detailed image with a different tone from the film Blade Runner, wishing to get past the smoke and chrome.

[6] Visual effects art director John Bell said that they had no script to work with, only the indications that the setting would be 30 years into the future featuring "something called hoverboards".

[8] To keep production costs low and take advantage of an extended break Fox had from Family Ties (which was ending its run when filming began), it was shot back-to-back with sequel Part III.

For a three-week period near the end of the filming, the crew split and, while most remained dedicated to shooting Part III, a few, including Gale, focused on finishing its predecessor.

Zemeckis himself slept only a few hours per day, supervising both films, having to fly between Burbank, where it was being finished and other locations in California for Part III.

[5] It also includes a brief moment of computer-generated imagery in a holographic shark used to promote a fictional Jaws 19, which wound up unaltered from the first test done by ILM's digital department because effects supervisor Ken Ralston "liked the fact that it was all messed up.

[16][17] Claudia Wells planned to reprise her role as Marty's girlfriend Jennifer Parker, but when filming coincided with a family cancer crisis, she chose to care for her mother's health.

[18] After the producers cast Elisabeth Shue as a replacement, they re-shot the closing scenes of the first film for the beginning of Part II, in a nearly shot-for-shot match with the original.

[21] Zemeckis said jokingly on the film's behind-the-scenes featurette that the hoverboards (flying skateboards) used in it were real, yet not released to the public, due to parental complaints regarding safety.

It uses a large superconductor plate on the bottom cooled with liquid nitrogen as to achieve the Meissner effect and allow it to float over a special track; it was shown capable of carrying the weight of a human in its practical demonstration.

[37][38] In March 2014, a company named HUVr Tech purportedly demonstrated a working hoverboard along with several celebrities including Lloyd, though this shortly was revealed as a hoax created by the website Funny or Die.

[42] Despite losing, one year later the Cubs did win the 2016 World Series against the Cleveland Indians;[43] in congratulations to the Cubs, the official Twitter feed for the Back to the Future franchise jokingly tweeted out that Marty & Doc's time-traveling caused "a rift in the space-time continuum" that led to the 1994 strike (and subsequent cancellation of the 1994 World Series), thus delaying the accurate prediction by a year.

The website's critics consensus reads: "Back to the Future II is far more uneven than its predecessor, but its madcap highs outweigh the occasionally cluttered machinations of an overstuffed plot".

[55] Janet Maslin of The New York Times wrote that the film is "ready for bigger and better things" and later said that it "manages to be giddily and merrily mind-boggling, rather than confusing".

[57] Jonathan Rosenbaum of the Chicago Reader gave the film a negative review, criticizing Zemeckis and Gale for turning the characters into "strident geeks" and for making the frenetic action formulaic.

He believed that it contained "rampant misogyny", because the character of Jennifer Parker "is knocked unconscious early on so she won't interfere with the little-boy games".

[58] Variety said, "[Director Robert] Zemeckis' fascination with having characters interact at different ages of their lives hurts it visually, and strains credibility past the breaking point, by forcing him to rely on some very cheesy makeup designs".

It was nominated in 1990 for an Academy Award for Best Visual Effects (John Bell, Steve Gawley, Michael Lantieri and Ken Ralston), but lost to The Abyss.

On December 17, 2002, Universal released it on DVD in a boxed trilogy set, although widescreen framing problems led to a product recall.