A loud, ugly, ungodly mess. It starts out with what's already the biggest pill to swallow in a time-travel adventure, and proceeds to let this snowball into a burden of disbelief such as could not be suspended by wire cables. Namely: the manufacture of a mobile time machine which, by nipping backwards and forwards in time but with slight alterations in geographical destination, can indefinitely multiply the number of places in which one person can manage to be at the same time. This all alone would be enough to sink the project, but there's much more. So much more, in fact, that there's no need to tarry over a logical expedience of the size of the one whereby our teenage hero, ca. 1985, turns out to have a son, ca. 2015, who happens to be a dead ringer for his dad at that age (as well as having an identical twin daughter, enabling Michael J. Fox, who is not yet threatening Roddy McDowall's record for Oldest Screen Adolescent, to dress up in drag and solicit titters from the sexually insecure youth audience). Much more bothersome is such a basic question of plot logic as why the villain (an actor who appears to believe the word "sneer" ought to be spelled with six e's), after having stolen the time machine, would then return it considerately to the exact time and place from which it departed. Further: in what sense can the past be said to have been altered if the chief beneficiary of the change must come back to the same miserable state of existence he occupied before the change? Hasn't he, along with everyone else, actually wound up with two separate, parallel lives? And what's to stop him -- what's to stop the filmmakers -- from going on to create twenty parallel lives? It probably doesn't bear thinking about. Or rather: thinking about it probably can't be borne. With Christopher Lloyd; directed by Robert Zemeckis.