OK, so it's basically "Big" with superheroes and villains instead of businesspeople and girlfriends, but director David F. Sandberg has infused his film with so much heart and charm that it hardly matters. Even the deficiencies, like the sluggish beginning and the random, ridiculous villains, fade away under a haze of goodwill because unlike so many big spectacle action pics with sequels in mind, "Shazam!" actually sticks the landing.