Guardians of the Galaxy opens with a musical number. OK, technically it opens with the perfunctory action movie exposition dump (mother dying, mysterious box that won’t open until the third act, alien abduction).

But after that bit of business come the surprisingly delightful opening credits, layered over a freewheeling dance on an alien planet, as Chris Pratt’s (The Lego Movie) Peter Quill flounces around among geysers and CGI lizards, a Walkman snug around his ears. There are visual references to Singing in the Rain and Raiders of the Lost Ark.

As a sequence, it’s as out-there as a summer tentpole can get. The same can be said of the movie around it: For much of its runtime, Guardians of the Galaxy is as weird as franchise filmmaking can possibly be in 2014.

Peter Quill is a thief trying to make his way in the galaxy. After he grabs a mysterious orb, he falls in with a ragtag band of fellow outlaws, including a genetically modified raccoon, Rocket ( Bradley Cooper, American Hustle) and his talking tree sidekick (voiced by Vin Diesel, Riddick, in the role he was born to play). There’s also a runaway assassin (Zoe Saldana, Avatar, here green-skinned, rather than blue) and a hyper-literal, vengeance-seeking hulk (wrestler Dave Bautista).

Guardians of the Galaxy cast

Director James Gunn  (Super) wisely unsticks his space opera in time, creating an aesthetic that nods at once to the sleek virtual future (spaceships, holograms) as well as the kitschy, tactile past (Troll dolls, that Walkman, wood paneling). The film’s design blends shiny technoscapes with grimy, ‘70s-inspired color schemes (oranges, yellows, browns, blues). There are conscious nods to Star Wars, Star Trek, and the ancient Aliens of H.R. Giger.

This pastiche-y playfulness extends to the acting. Cooper voices Rocket with a fast-talking Brooklyn patter; when the tiny animal bounces off his dumb brute sidekick, it goes beyond homage: It’s vaudeville, through and through. When Benicio Del Toro shows up in a cameo, he’s doing Rocky Horror. Saldana plays it straight. A newly-chiseled Pratt smirks his way through the film; he’s James T. Kirk by way of Kevin Bacon in Footloose, and he somehow manages to keep those explicit reference points from becoming glib.

Of course, because this is a Marvel movie in 2014, everything around Saldana and Pratt – even the raccoon – is digital. But for Gunn, who made his name through hand-crafted high camp homages (as in the gloriously discomforting Slither), the CGI still feels fresh. He and his cinematographer, Ben Davis, shoot like Zack Snyder, all swoops and slow motion, but Gunn has none of Snyder’s drab workmanlike professionalism. Nor does he shoot his virtual world with the resigned indifference of, say, a Michael Bay.

Instead, Gunn makes you feel every piece of CGI trickery, from that first alien dance scene to the final ship crash; you can feel him reveling in his new multi-million dollar playground. It would not be (too) hyperbolic to say that there are (a few) moments in Guardians that rival last year’s Gravity for casual beauty. There is a moment where nebulae explode in the background while our heroes glide through zero gravity. At one point, fireflies light up a darkened spaceship. The film stops to admire these moments as you do. It’s refreshing.

Guardians is not without its flaws:  The film’s big bad falls victim to Generic Action Villain Syndrome, squandering the extremely talented Lee Pace (The Hobbit, but unrecognizable here under crunchy blue and gray face paint and a deeply modulated voice). The movie occasionally feels burdened by its need to tie into the Marvel universe (and an already greenlit sequel), and it burns out its go-for-broke energy as it goes along, eventually giving way to more generic action adventure beats. Characters have an unfortunate tendency to shout subtext, and the whole thing is ten minutes too long.

But these don’t mar a genuinely engaging, fun piece of pop filmmaking, one with a healthy sense of restraint, a killer soundtrack, and a sense of humor that dabbles in the sort of self-referential black comedy that belongs in the grindhouse more than the megaplex.

For the most part, Guardians of the Galaxy zigs where you expect it to zag, taking the contours of the Marvel blockbuster and finding wry, winking directions to take them. It’s refreshingly cartoonish, and as close to gonzo as modern blockbuster filmmaking gets.

At least until they make three or four more.