The beginning of the film, which is the ending of Part I, had to be re-shot, as the role of Jennifer had been recast.

When Marty is waiting for Griff in the cafe he plays a videogame with two young boys. One of the boys is a very young Elijah Wood.

In the scene where Marty is scared because of the holographic picture of the shark coming from the 'Jaws 19' thing, if you look closely you can see 'Directed by Max Spielberg'. Steven Spielberg who directed the first Jaws has a son named Max.

The tunnel that Biff Tannen and Marty McFly both go through, is also the same tunnel seen in Who Framed Roger Rabbit.

The film was shot simultaneously with Part III. In the five years since the original film was made, Michael J. Fox had forgotten how to ride a skateboard.

Towards the beginning of the movie there is a close-up of the front window of Blast From the Past. If you look closely in the upper left hand corner you can see the jacket that Marty wore in the first movie. Also if you look on the right hand side you can see a "Who Framed Roger Rabbit" doll, another Robert Zemeckis film.

In the scene where young Jennifer is in her future house, her daughter-to-be, Marlene, comes down the stairs. Marlene says, "Mom? Mom, is that you?" - the same quote used by Marty three times throughout the trilogy when he wakes up in bed, after being knocked out.

Vaguely interesting point - when Doc and Marty arrive back in 1955 to stop the handover of the Almanac, there are actually 4 versions of the same time machine in the area at that time. The one they've just arrived in from the alternate 1985, the one Marty arrived in from the original 1985 in the first film, the one Biff's arrived in from the future, and the one Doc's buried from 1885. Submitted by Jon Sandys

Much of Griff's outfit, particularly his boots are bits of Klingon costumes from Star Trek: The Next Generation. Submitted by Grumpy Scot

When Marty is in the Cafe 80's, when he is about to hit Griff or get hit by Griff, you can see a row of TVs behind them (showing the Smurfs, etc). One of the TVs is showing Family Ties, the show that made Michael J Fox famous.

This isn't really a mistake, more of a thing to know. In Back to the Future II, Biff is watching the Clint Eastwood movie "A Fistful of Dollars." If you have seen this, you know that at the end, Clint uses a piece of metal to stop all the shots from Ramon. In "Back to the Future III" Marty calls himself Clint Eastwood and at the end, he uses a piece of metal to keep himself from dying.

In the scene where the Doc of the future, hands the 3/4 wrench to the Doc of 1955, the Doc of 1955 is wearing the same two watches that the other Doc wears throughout the entire movie. This could actually happen if the Doc of 1955 kept the same two watches to wear throughout his life. It's still worth a look.