5 blatant Back to the Future mistakes

I've realized I'm woefully inadequate at using this blog for movie news, etc., not least because there are loads of other places that do that, so instead I'm stick to this site's strengths, namely picking movies apart as only a true fan can. I've been asked in the past what the appeal is of mistake spotting, and while there are loads of different potential reasons, for me it's all about the relatively minor but obvious things - the stuff which most people wouldn't notice first time around, but once they're aware of it they'll never be able to ignore it again. Maybe I'm just evil like that. Anyway, here are a few things from Back to the Future you might never have noticed before:

Vanishing hairdryer

Probably the most obvious one, this - during Marty's "Darth Vader" appearance to his dad, he's got a hairdryer tucked into his waistband in some shots, but it vanishes in others. The reason for this is that this scene was meant to be longer, including a part where he removed it, but that part got cut out, meaning it just leaves a big ol' continuity problem.
Disappearing speaker

Also very obvious, but only once you look for it - when Marty's first wandering around town, he sees a car drive past with speakers on the roof, campaigning for someone. All well and good, but in the following shot where it moves past him, one of the speakers has suddenly vanished, and the poster on the roof's turned itself around 90 degrees.
The self-emptying sweet jar

Simple but blatant, this one - near the start there are some sweets in a jar in Marty's house, full mostly to the top. Biff goes over to take some, and the jar's suddenly half full.
Dials all over the place

This one was surely unavoidable, and also requires quick eyes - it's during Marty's chase around the car park with the terrorists. In various shots we see his speedo as he gets faster or slower, but look at the numbers on the odometer and trip counter, rather than the speed - they jump around all over the place despite the chase only lasting a couple of minutes. The needle on the speedo changes to, from having an angled bottom to a flat one - clearly a completely different car's instrumentation!
The Doc impersonator

Last, and probably least, but also the silliest - right at the end, when Doc crashes into the bins, take a close look at who's driving. It's not Doc, but a fatter stunt driver wearing a really bad white wig.
And finally...

As a final bonus for you to check out yourselves, take a look at the DVD when Einstein's in the time machine and Doc starts it reversing. Doesn't really work caught as a picture, but if you watch it in motion it's easy to see that it's just a stunt driver in a dog suit - you can even see his hands turning the steering wheel...