Just like in Back to the Future Part II, Zemeckis, screenwriter Gale, the effects crew and the cast make the best possible use of the time travelling mythology. Whereas Part II gave us a startling glimpse into the future, they use Part III to give us a film that pays homage to a genre they obviously all love, the Western.

It's everywhere from the sequences directly copied from great westerns to the flourishes of trivia, like Marty's oven-front bullet proof vest, which he got the idea to do from A Fistful of Dollars &ndash: remember, Biff was watching it with his bimbos in his hotel bath in Part II.

Gale expertly weaves the continuing story of Marty and Doc's travels through time in Hill Valley, California through some of the most recognisable western fixtures we all know. And it doesn't let one aspect of the story (the western versus Doc and Marty's plight) overshadow the other for a minute - even if you hate westerns, it's as much fun and as satisfying as Part II was.

We left Marty running back into town during the November 1955 thunderstorm that lashed Hill Valley to find the Doc who's just sent Marty back to 1985 and get his help to find the older Doc, the one the storm has sent somewhere off in history. The letter left in the post office's possession that was delivered to Marty at the end of Part II contains instructions to find the time machine hidden in a cave - where it's been for seventy years, awaiting the 1950's when the technology exists to fix it.

With the 1955 Doc's help, Marty travels back to 1885 to rescue Doc from the death he knows is coming at the hands of the Tannen gang, led by Biff's grandfather Buford. It's not easy. While fixing the time machine and refitting it for use on train tracks, Doc falls in love with the new teacher (Steenburgen) whose life he saves from a fall into the local ravine.

Aside form the western homages and trivia, it's full of fixtures unique to the Back to the Future series, from the town bully (one of the Tannen family) coming into the watering hole shouting 'Hey McFly!' to the Hill Valley clock tower that will stop forever in 1955.

It was an inspired move and something of a risk by Zemeckis, Gale and Universal to change a small romantic comedy film to a full-blown sci-fi franchise, but the result merely proved fans of the original loved the sci-fi aspect. A worthy final chapter to one of the most enjoyable movie series ever.