In the past couple of years, Dreamworks Animation has made a shift from movies like Shark Tale and Shrek to higher-quality works like Kung Fu Panda (sequels excluded), the hugely underrated Megamind, and How To Train Your Dragon, which garnered a near-Pixar 98% "Certified Fresh" score on Rotten Tomatoes. In fact, the rise of Dreamworks seemed to coincide almost perfectly with Pixar's micro-fall from public graces: Cars 2 was widely panned, Brave was widely criticized as being good but somehow not very Pixar, and the movie studio canceled several in-development new properties while renewing older films for sequels.
It seemed for about six months, after 2012's Brave marked Pixar's second underwhelming film in as many years, that Dreamworks Animation could overtake Pixar, if not in quality then just in sheer public goodwill. It was hard for Dreamworks to disappoint people when nobody expected anything, and the exact opposite was true for Pixar.
Well, to anyone else who follows the vacillating fates of Pixar and Dreamworks Animation like most people follow sports teams: it was a fluke, guys, we can go on home. Turbo is a staggeringly average showing for the studio, as shallow and transparently message-laden as anything Dreamworks Studios has produced in years.
(There is one bright spot, though: a running joke about crows unexpectedly snatching snails and flying off with them, presumably to the snails' doom, got the hardest laughs from me. But notably, none of the children in the theater seemed to agree with me.)
The film centers around a snail named Theo (voiced by Ryan Reynolds) who dreams of racing in the Indy 500. After a pleasantly surreal encounter with a car engine full of NO2, Theo is granted super-speed, rechristens himself Turbo, and sets out trying to achieve his dreams. Because, as the movie repeats over and over, "No dream is too big, and no dreamer too small." (My apologies if my summary of the movie is almost word-for-word identical to those you'll find on other sites, but the movie just isn't complicated enough to mention anything else.)
The movie is filled with the kind of star-studded cast that's become problematically typical of Dreamworks animated movies, but I'm not going to list anyone besides the near-unrecognizable Bill Hader (who plays Guy Gagne, Turbo's inspiration-turned-competition), because none of the stars get more than 30 seconds of dialogue—in fact, one could almost cut the movie down to a five-character show and lose nothing. Bit parts are there to pad length and turn familiar, likable voices into goodwill for the movie, like in the case of criminally-underused Maya Rudolph (who, in a weird note, is listed on every synopsis I've read as being Turbo's love interest, despite the fact that this is definitely not true).
However, the movie can definitely be enjoyed by six-year-olds who want to watch a snail go fast. It's free from the problems of sexual and gastrointestinal references that turned parents off to movies like Shrek. It is not too long. All around, it's not worth seeing in theaters, but I guess there's no reason to actively avoid it.