When you lay down money to see a movie called "Teenage Mutant Ninja Turtles," your expectations -- understandably -- are that you'll see plenty of these martial arts-trained reptiles. Yet the 2014 release failed fans of the decades-old franchise, delivering a gritty reboot that forgot the fun of these heroes on the half-shell, making them a seldom-seen sideshow act to an uninspired April O'Neil adventure, where the brave journalist was more ogled than aspirational. However, Michael Bay's production company has radically course corrected with the aptly titled, "Teenage Mutant Ninja Turtles: Out of the Shadows," which not only puts the brawny brothers at the center of the story where they belong, but also folds in a cavalcade of other fan favorites, like Casey Jones, Kraang, Bebop and Rocksteady. Undeniably better than its predecessor, this spirited sequel offers more laughs, more fun and more turtles, but some of the same old disappointments.

"Teenage Mutant Ninja Turtles: Out of the Shadows" begins with an action-packed and ardent apology to fans. Right out the gate, Donatello (Jeremy Howard), Leonardo (Pete Ploszek), Michelangelo (Noel Fisher) and Raphael (Alan Ritchson) leap from the heights of Manhattan's skyscrapers and into the film's spotlight, bounding through hidden tunnels to take in a Knicks game and chow down on an NYC slice of pizza. Then they skateboard through sewers, weaving down them with a waterslide splash that wipes away that foul taste the last film's angst-ridden teens and turtle boner jokes left behind.

RELATED: Vanilla Ice Performs "Go Ninja Go Ninja Go!" at "TMNT: Out of the Shadows" Premiere

Strapped into complicated motion-capture suits, Howard, Ploszek, Fisher and Ritchson give dimension and individuality to each turtle, with an assist from some next-level animation and visual effects. It's a total blast to watch these brothers come to life and interact, whether they're goofing around high above the city, or battling baddies on land, in white water rapids, or in the air. That elevator scene fans cheered last time has been a clear guide, giving this sequel a much-needed boost of energy, comedy and character.

Speaking of characters, the scene gets crowded quick. April (Megan Fox), her loud-mouthed cameraman Vern (Will Arnett), and Shredder (Brian Tee) are all back, but joined by new menaces and minions. Tyler Perry brings his bombastic comedic appeal to Shredder ally/mad scientist Baxter Stockman. Character actor Gary Anthony Williams relishes in a beastly bromance with WWE star Stephen "Sheamus" Farrelly, playing Bebop and Rocksteady respectively. Brad Garrett offers some out-of-this-world lunacy and villainy as the voice of the would-be conqueror Kraang, three-time Oscar nominee Laura Linney delivers welcomed gravitas to this gleefully goofy superhero tale as a no-nonsense police chief, and "Arrow" star Stephen Amell gives a curious take on the hockey-loving vigilante Casey Jones. As you might guess, all this makes for an overstuffed storyline.

The plot is a mess of strange quests, personal vendettas, chase scenes and heavy-handed messages about self-acceptance. But it's hard to give a hoot when the sequel delivers so much gonzo action! Whatever their half-cocked setups might be, I'm stoked to see so much of the turtles, and so much of them kicking ass. One especially stupendous sequence that's getting a lot of love in the trailers involves a battle with Bebop and Rocksteady that takes the brothers from an eye-popping skydive to a plane brawl unlike any you've seen before, to a climax in the raging waters of a far flung jungle. Every frame the turtles are on screen is a total thrill. A long-time fan of the Turtles, director Dave Green ("Earth to Echo") infuses the film with Easter eggs and enthusiasm, and offers plenty of chances to enjoy these heroes, like a particularly elating moment when a highway chase scene goes slo-mo so we can share in Raph's unadulterated joy of barreling into two motorcycle-straddling baddies.

The Turtles are awesome. I'm tempted to tell you to see "Teenage Mutant Ninja Turtles: Out of the Shadows" for them alone. Likewise, their mutant rivals Bebop and Rocksteady offer wild fun, wacky laughs, and a strangely charming sense of fraternity. Unfortunately, the movie falls flat with its humans.

Supporting players like Arnett and Perry do right by the film's tone, basically playing their parts like live-action cartoons. But Fox and Amell are jarringly dull in the lead human roles, offering onscreen chemistry that's inert rather than intoxicating. This new Casey Jones is a fast-talking corrections officer, frustrated by the red tape in his way of recapturing the Shredder. But despite Amell's pluck, he fails to capture the sense of alluring danger that made Elias Koteas's Casey such a strong foil to the Turtles back in the '90s. As for Fox, she gives her standard performance, full of batted eyelashes in lieu of anything resembling emotion or charisma.

I don't know how you course-correct Paramount's rebooted April O'Neil, aside from recasting and retconning. Platinum Dunes tries neither, opting instead to kick Fox to the fringes. In 2014's "Teenage Mutant Ninja Turtles," April was a regretful protagonist, a journalist who lacked the communication skills to convince anyone of the incredible things she saw. Here, she's so inconsequential to the plot that most of her screentime is spent nodding as others talk, or waiting around for someone else to make a move. Fox's big moment comes early on in a convoluted sequence that lamely offers the thinnest excuse to squeeze the gorgeous starlet into a school-girl fetish costume. When Michael Bay is a producer, is it in the fine print that a female lead must strut in slo-mo while wearing a tight, white blouse to be obligingly leered at?

Those who hoped the inclusion of Shredder's right-hand woman Karai would give us a female character worth a damn will be sorely disappointed. While Brittany Ishibashi carries herself with purpose and menace, her Karai is little more than intimidating arm candy for the similarly shafted Shredder. The sequel is too overloaded for all these characters, so many of them underserved, to make room for a big intergalactic baddie. Having mutated the franchise's fierce female journalist into a lackluster centerfold, "Teenage Mutant Ninja Turtles: Out of the Shadows" casting of Linney as an in-charge cop seems a half-hearted recompense. Linney is great, winning bonus points because it's innately hilarious to see an actress of her caliber in such a dedicatedly silly movie. But I still want an April O'Neil I give a damn about. That a cameo of Judith Hoag (the original trilogy's April O'Neil) got cut, just adds insult to injury.

Frankly, I'm a little frustrated by Platinum Dunes' refusal to recognize that women and girls love the "Teenage Mutant Ninja Turtles," too. I was having an absolute blast watching the brothers gallivant about New York City in their tricked out Turtle van, shoveling enviable amounts of pizza in their faces. But every time April popped in to flip her hair or flash a blank smile, it felt like a slap in the face. With so much reshaping in the wake of the last movie, was it too much to hope the filmmakers behind this franchise might realize there's more to April O'Neil than curb appeal?

"Teenage Mutant Ninja Turtles: Out of the Shadows" opens Friday.