It's not surprising that 17 Again is an absolutely formulaic and predictable movie, but despite that and its other numerous flaws, it comes off as disarmingly sweet with some genuinely likeable moments and performances, especially from Zac Efron and the always terrific Leslie Mann. The former, undoubtedly trying to break away from his pre-teen Disney-mold, actually manages to come off slightly cooler to those who don't have curfews in this well-chosen transitional role as a depressed, almost divorced father who suddenly finds himself back in his 17-year-old body.

The movie starts in a place probably most comfortable for pre-teen fans of Efron and painful for nearly everyone else: it's the '80s and teenaged Mike O'Donnell (Efron), Stamos-esque locks a-flowing, is warming up for the big basketball game by busting out a few overly-choreographed moves with the cheerleading squad. But the movie quickly veers away from this pre-teen trap of an introduction when it is wordlessly revealed that O'Donnell's girlfriend, Scarlet, is pregnant. He "throws" the game and a chance at a college scholarship away to be with the girl he loves. For what it is, it's a genuinely sweet moment and reveals O'Donnell not only as the popular jock, but as a kind kid with a good heart and good intentions.

Skip to the present and O'Donnell (played by a positively bloated Matthew Perry) is a rumpled and dejected 40-something crashing on his convenient millionaire best friend Ned's couch. Ned is a nerdy role so obviously and randomly inserted for comic relief but manages to work with Thomas Lennon (from I Love You, Man and Reno! 911) spouting Elvish and Star Wars proverbs throughout and wooing the principal (The Office's Melora Hardin) in an endearing side story.

But back to the main bit, the adult O'Donnell is stuck in a dead-end job and has completely alienated himself from his wife (Mann) and children. So, of course, he dreams of going back and redoing things and gets his wish when -- mashing up It's a Wonderful Life and Big in reverse -- a janitor cum angel leads him off a bridge into a swirly vortex, and ta-da, it's Zac Efron in an oversized suit.

It's at this point that the movie really picks up. Following an amusing montage basking in his former youth and fitness, O'Donnell discovers that it's not really his life that he's meant to re-do, but rather he's to help out his messed up, unfortunately two-dimensional kids in a sort of reverse Back to the Future section. In some very satisfying scenes, O'Donnell befriends his socially awkward son, confronts the "Biff"-type bully in a cafeteria speech that points out all the psychological reasons why this kid is so messed up and fights the same bully, who turns out to be his daughter's boyfriend, over a basket of condoms and a rousing pro-abstinence speech.

Efron is pretty convincing, likeable and funny playing a concerned father in ways reminiscent of Michael J. Fox in Back to the Future. Also, like Fox, he manages to pull off some uncomfortable moments rebuffing some unwanted incestuous advances. The teen version of O'Donnell has a strange chemistry with his estranged adult wife, too, but despite the odd cougar moment, Mann and Efron bring the original love story -- which genuinely feels at stake -- back to the fore in surprising ways.

The ending is also not as big a cop-out as expected because the story of re-discovered love is carried off so well by Efron and Mann. The final scene not only offers Efron a chance to showcase his actual and somewhat unexpected acting range, but is one of the better written moments of the movie. Though it is derivative of so many time-travelling movies, 17 Again works thanks to some likeable actors, not least of all Efron, who deserves more credit than his thought-to-be-empty good looks and resume lend him.