No movie this summer will leave your jaw on the floor and your eyeballs as wide as saucers like Luc Besson’s Valerian and the City of a Thousand Planets. The latest from the French filmmaker is a dazzling feast of spectacular visuals and exhilarating set pieces. It’s Besson’s most ambitious film to date, and the most original big-budget adventure you’ll see on screen this season. But such ambition doesn’t always come without flaws.

Based on the French graphic novel Valérian and Laureline from writer Pierre Cristin and artist Jean-Claude Mézières, Besson’s film follows Dane DeHaan’s Valerian, a cocky special agent who spends most of his time wooing his partner Laureline (Cara Delevingne). After completing a mysterious mission where they rescue a rare creature from a black market trade, Valerian and Laureline are sent to Alpha, a giant space station where thousands of alien species have been living in harmony for years. Alpha is the epitome of world peace, a bustling metropolis where various species share their knowledge, languages, and scientific discoveries to form the ultimate futuristic society. But when Alpha’s military commander Arun Filitt (Clive Owen) detects suspicious activity in a remote area of the space station, the Defense Minister (Herbie Hancock) sends Valerian and Laureline to Alpha to investigate a potential threat.

An independent French production made for $180 million (the most expensive in the country’s filmmaking history), Valerian may have the budget of a Hollywood blockbuster, but it looks and feels nothing like one. Besson’s space opera is weird and quirky in ways you’d never see in a contemporary American tentpole movie. This is a movie in which Rihanna performs a burlesque show as a shape-shifting alien, Cara Delevingne shoves her head inside of a jellyfish, John Goodman has a one-scene cameo but you never see him in the flesh, and the plot revolves around a cute creature’s magical poop. That sense of weirdness and spirited personality — along with Besson’s bonkers set pieces — is what makes Valerian so unique and satisfying to watch. One fantastic action sequence uses virtual reality and alternate dimensions to up the stakes of a basic heist, then pivots into a full Fury Road-style chase against a monstrous alien. And after all that, Besson even finds some serene moments between his alien creatures.

Valerian is easily Besson at his most imaginative since The Fifth Element, creating a canvas that’s bursting with originality. This is world building at its finest, and Besson’s futuristic landscape is so richly textured that you’ll find your eyes scanning each frame to soak up all the intricacies and details. This movie is glowing with brightly-colored aliens, mouth-watering space vistas, and shiny, innovative weapons; if you’re going to fork out the extra cash to see any movie in 3D this summer, make it this one.

But as beautiful as Valerian is to look at, it’s also a bit frustrating to watch. The first hour and change is a well-crafted space adventure filled with wild, head-rushing set pieces, mesmerizing world building, and humorous banter. But about halfway through the film’s 137-minute runtime, the narrative becomes repetitive and the pacing slackens to an aggravating degree. The jokes don’t land as well as they could and the momentum of the final set piece fizzles out. It’s a shame because I want to love every bit of this movie, but ultimately found myself waiting for it to end. Much of that could’ve been solved by generous editing, but some of its problems are also due to the casting.

DeHaan might play the title character, but he’s easily the least interesting part of the film. He plays Valerian with a haughty indifference and cold, bro-y demeanor. The actor employed a similar approach with A Cure for Wellness earlier this year, and it worked wonders within the eerie, icy terror of that movie. But here it strips Valerian of all his charm. DeHaan tries to make Valerian’s cheeky insouciance alluring and sexy; instead, he comes off stiff, passionless, and a bit irksome. Casting a lanky, boyish type like DeHaan as a dashing ladies-man hero is a much more interesting choice than the predictably strapping Hollywood type. Points for trying, but DeHaan just wasn’t the guy for the job.

It also doesn’t help that DeHaan and Delevingne have absolutely no chemistry. Valerian and Laureline’s push-and-pull flirtation is supposed to form the foundation of trust and compassion that ultimately shapes the film’s theme. But you just never buy it from these two actors who look increasingly awkward on screen together. You get the feeling that Delevingne tries to toss a couple sparks DeHaan’s way, but he never bites. On the other hand, Delevingne plays Laureline with a plucky charm, spinning even the most stale dialogue into playful one-liners tinged with attitude. The model-turned-actress is becoming one of the more interesting young performers to watch. There’s still a stiffness to her onscreen presence, something I can imagine will dissipate as she continues to act more and get meatier roles, but she still lends the film a bubbling energy, even in its duller moments.

With about 30 minutes shaved off the runtime, tighter editing, and a stronger lead performance, Valerian could’ve been in the running for the best movie of the summer. And yet even with all its flaws and kinks, I still admire its wacky spirit and simply awe-inspiring visuals. I’ll still take Besson at his wildest, as imperfect and messy as it may be.