Writer-director James Gunn’s Guardians of the Galaxy Vol. 3 pushes Marvel’s devotion to the PG-13 rating to its limits and probably isn’t suited for younger audiences who aren’t accustomed to films featuring graphic violence, animal cruelty and thoughtful depictions of complicated adult problems. Frankly, the film doesn’t really feel appropriate for audiences who found themselves charmed by the cheerful irreverence of Gunn’s first two Guardians films, which popularized the colorful jukebox-action aesthetic that has dominated the mainstream action space over the last decade.

That’s not to say Vol. 3 lacks comedy; it may well be Gunn’s best script of the three, constantly funny and clever. But it also approaches the characters’ underlying traumas in an unsparing and, frankly, more adult fashion. Rather than simply continuing to tell stories about the Guardians facing their traumas and laughing, Gunn lets his core cast grow and evolve, finding a fitting ending to his trilogy that may not appeal to everyone but feels as honest as anything Marvel Studios has ever released.

The story picks up a few years after Avengers: Endgame (and shortly after The Guardians of the Galaxy Holiday Special … and, I suppose, Thor: Love and Thunder, but the less spoken of that film, the better). Our heroes have refurbished Knowhere, a city built inside the head of a dead Celestial (as seen in Eternals). They’re pseudo-administrators for the domain, which houses refugees and other homeless citizens of their local sector.

Rocket (portrayed by Sean Gunn in motion-capture with Bradley Cooper’s voice), Peter Quill (Chris Pratt), Nebula (Karen Gillan), Drax (Dave Bautista), Mantis (Pom Klementieff), Groot (Vin Diesel) and Kraglin (Sean Gunn, for real) are at high points in their lives as heroes and, for some, low points in their lives as people. Peter is a depressed drunk who can barely stand up straight most nights, pining for everyone he’s lost: as a child, his mother; in Vol. 2, Yondu (Michael Rooker); and in Avengers: Infinity War, the love of his life, Gamora (Zoë Saldaña). Rocket, meanwhile, remains the same angry and crotchety little furball he’s always been, having found his family but no solace for the trauma of his existence.

Their relatively quiet lives are shaken when Adam Warlock (Will Poulter) appears from the skies, viciously beating them in an attempt to kidnap Rocket for the High Evolutionary (Chukwudi Iwuji), who is seeking the raccoon’s brain for further experimentation. We learn pretty quickly Rocket was a normal raccoon altered as part of the madman’s mission to create a “perfect world” out of what exists. Over the course of the film, we’re treated to flashbacks of Rocket’s tragic early life. And it is very, very tragic.

So tragic, in fact, that its intensity might extend beyond alienating fans of the first two Guardians films; perhaps it’s too much even for the wider audience that has made Marvel the keystone franchise for a decade-and-a-half of popular culture. Having come from the world of Troma films – a skillset he used for his first DC-based film, The Suicide Squad – Gunn has never been one to shy away from gore and violence. But this time, it’s different. He doesn’t play it for humor or relief, which has always been Marvel’s way of having its cake and eating it, too, when it comes to death and destruction wrought by its heroic figures. This time, violence is largely played as a horrific, terrible thing that begets only loss and pain.

This is very much Rocket’s movie, but it’s also the best showing for his entire found family of misfits. Peter finally gets to be more than a petulant man-boy, and his own journey through grief and pain provides him a conclusion that may come across to some as understated but feels more genuine than anything else he’s gone through thus far. Pratt seems to know it and gives the character a pathos he’s previously lacked. Nebula has always lived in the shadow of her sister throughout these films, but Gillan has so much more to do this time around and nails this upgraded version of her character. As seen in the holiday special, Gunn knows how to use Klementieff and Bautista as a comedic duo but also understands the sweetness of their bond. They shine here, as their childlike characters represent perfect perspectives for a story that ultimately argues empathy is the strongest power of all.

As such, the lack of empathy is the fundamental flaw with Iwuji’s ferocious High Evolutionary. He isn’t one of Marvel’s standout villains – he doesn’t view himself as the hero of his own story like Loki or Thanos, for instance – but he has a specific role in Gunn’s story, and Iwuji understands the pain and anger that drive his psychopathic mad scientist to continually create and destroy his own children. Sure, it’s arguably an extension of the same “authoritarian villains versus free heroes” dynamic that fuels most of Marvel’s output (and the very specific Evil Father trope found in all Guardians films). But unlike its predecessors, Vol. 3 doesn’t attempt to humanize this bad dad. More so than the other films, he is a catalyst by which the Guardians grow to better understand each other and themselves. He’s a character properly utilized to tell a story that isn’t just “good guys stop bad guys by confronting their daddy issues.”

Like Avengers: Endgame, Vol. 3 is a conclusion to its saga and, as such, probably won’t land with everyone. These are characters fundamentally designed to face iterations of their basic trauma ad nauseam, never quite growing beyond their original forms. What is Peter Quill if not a man spitting wildly in the face of the grief that haunts him? Who is Rocket if not an angry misfit who pushes everyone away due to the terror of his birth? Who is Drax if not a man driven to vengeance by the loss of his wife and child? Endgame gave endings to three of the primary Avengers characters to mixed success. This film crafts satisfying conclusions for each of its characters’ journeys and deftly understands the most honest goodbyes might just come from knowing when it’s time to move on. That isn’t to say there aren’t big, bombastic moments in Vol. 3, but its key emotional insight when bringing its little corner of the MCU to a close is that change can mean death, but it can also mean growth.

Maybe that’s a lesson of which the broader MCU should take heed. I’m gushing a bit, but truthfully, Vol. 3 is the first Marvel release that has grown on me throughout its runtime in a very long time. Phases 4 and 5 have had a lot of films and shows that just didn’t quite work for me, and with few exceptions, it’s been a relatively dispiriting few years as a fan of Marvel Studios’ work. We’re already in the waning days of the franchise’s first golden age, and let’s not pretend there won’t be a resurgence at some point, given the cyclical nature of this stuff. But Vol. 3 may not be the film to bring whole families back into the multiplex. It feels destined to be a favorite for some ardent fans and detested by others due to the unsparing nature of its content and the way Gunn has eschewed the other films’ irreverent glee in favor of something more nuanced and, frankly, more mature. For my money, it’s one of Marvel’s better movies, and perhaps one of its best.