Pacific Rim Charlie Hunnam, Idris Elba, Rinko Kikuchi, Charlie Day. Directed by Guillermo del Toro. Rated PG-13. Opens Friday.

Filmmaker Guillermo del Toro has said that he wanted Pacific Rim to capture the perspective of a 12-year-old boy who loves giant robots and monsters, but watching the movie makes it seem like del Toro isn’t giving 12-year-olds enough credit. A movie meant to capture the imaginations of kids of all ages shouldn’t feel like it was actually written by a pre-teen, with dialogue paraphrased from mediocre comic books or episodes of Mighty Morphin Power Rangers. Pacific Rim might not be the worst large-scale blockbuster of summer 2013, but it’s the one that seems proudest of its stupidity, almost daring the audience to sit through terrible, clumsy dialogue delivered by actors who’ve left their charisma at home, all for the privilege of watching computer graphics fight each other under cover of darkness.

For a movie whose appeal is so basic (giant robots fight giant monsters!), Pacific Rim comes with a lot of superfluous backstory, which is laid out in lengthy, tedious narration at the beginning of the movie. The bottom line is that huge monsters from another dimension (called kaiju) have invaded Earth through a portal on the ocean floor, and scientists have developed giant robots (called jaegers) controlled by human pilots in order to fight the invaders. Sons of Anarchy’s Charlie Hunnam plays the hotshot pilot whose maverick style is just what’s needed to take down the kaiju. Idris Elba plays the stern but wise commander who enforces the rules but understands the need to sometimes break them. It’s Always Sunny in Philadelphia’s Charlie Day plays the scatterbrained scientist with a crazy theory about defeating the kaiju that just might work! And so on.

Del Toro favorite Ron Perlman shows up briefly to play the only interesting character in the movie, a snappily dressed trader in black market kaiju parts, but he doesn’t last long. Instead, del Toro slogs through unconvincing character drama in between loud, murky battles, combining some of the cheesiest elements of Voltron and pro wrestling (each kaiju, potentially deadly to the entire human race, gets a badass nickname). As the rare big-budget action movie not based on an existing property, Pacific Rim may be a labor of love for del Toro, but for the audience, it’s just a chore.