The larger that bombast grows, in modern action-fantasy cinema, the less it weighs. Transformers: Age of Extinction is composed entirely of hot air, so it balloons over the planetary map for 166 minutes, bombarding us with metamorphic metalware. That doesn’t weigh anything either, since the mechanoid mutants (some small and endearing, others as tall as the Empire State Building) were all created in cyberworld. Result: a movie mega-soufflé. Sweet, swollen with box-office self-importance, and probably just what the kids want for midsummer dessert.