Everyone loves a time-travel movie. Everyone. It’s the ultimate dream; to be able to flit back through time and tell your younger self to stop after the sixth Jägerbomb; to flit forward in time and find out the lottery numbers; to visit the dinosaurs (ill-advised) or our inevitably dystopian future (iller-advised). Of course, it’s all fantasy, and the fact that it’s impossible causes all sorts of consternation among nerds, who try and puzzle the various internal logics of such films until the wee small hours. Time-travel movies are great; but they’re also bloody confusing.