Leaving aside the similarities (or lack thereof) with Asimov’s Robot stories, this is an unbalanced film. The plot turns on an intellectual premise, but relies on Will Smith as a wise-cracking, muscular, lone action hero. Without Smith, this could have gone down as a clever piece of science fiction, but it wouldn’t have been a blockbuster, and it might not have got made in the first place. With Smith, it feels simultaneously watered down and pumped up, an awkward fit for an otherwise interesting script. Good fun, but not without its failings.