The first rule of watching any sci-fi: suspend your disbelief. Once you've done that you can enjoy the film which pretty much sums up the plots of every other time-travel film! That's used in a good way in this film - a whole load of solid, thought-provoking ideas are thrown in, yet Scott manages to make the film accessible - perhaps skipping over the science aspects of time-travel but crucially not disregarding them. What's more he makes sure it's a really enjoyable experience to see this film, whether or not you understand it. He directs here like Michael Bay, every shot aspiring to be named cool. But what'll really keep you at the edge of your seat is the terrific Denzel Washington. It seems that with age he's becoming more and more of a reliable action star. And that's just it - compared to his other films this is just great fun: with Washington and Scott there's a young Halle Berry lookalike, Val Kilmer as Washington's link to the Torchwood-esquire setup he's got going, and that dude you'll inevitably recognise from a load of places, who acts as the in-joke machine (to a smirking Kilmer) with references to Airplane, the classic 'More cowbell' SNL sketch, and godknowswhatelse! All in all this is ideal for rental, though certainly you wouldn't be ashamed to own it on DVD. High-quality popcorn film, which doesn't try to steal the thunder from the films it gets it's ideas from. See it.