Having saved the world umpteen times from Independence Day (1996) to I Am Legend (2007), Will Smith here clearly relishes the chance to muddy his nice-guy image. As scummy superhero John Hancock, he casually nails inspired gags like flying under the influence and bringing a speeding train to a crashing halt simply because he can't be bothered to lift the car in its path. Luckily, the absent-minded motorist is PR expert Ray Embrey (Jason Bateman), who promises Hancock the renewed adulation of a sceptical public if he'll only smarten up his act a bit. Bateman (star of sitcom Arrested Development) is the perfect comic foil for Smith but, sadly, their work is undermined when Hancock falls for Ray's wife (Charlize Theron). From then on the film itself threatens to implode, as a daft twist and a heavy dose of melodrama jar with the wit and freshness that has come before. Fortunately for director Peter Berg (Very Bad Things, The Kingdom), Smith has enough superstar powers to rescue us all from crushing disappointment.