You can have too much of a good thing. Having recently gorged myself on the entire first series of Alias on DVD over a weekend I know that statement is not unequivocally true. But even allowing for the vagaries and relativism of personal taste, halfway into Terminator: Salvation I began to believe it. It wasn’t the stunning CGI; it wasn’t the stunning set-piece action sequences; it wasn’t the scarred, bleached-out but atmospheric post-apocalyptic landscape; it wasn’t the gloomy, cramped underground boltholes of what is left of the human race after Judgement Day, scurrying for survival like rats in the shadows.