Robert Downey Jr. is 48 and feeling it. Especially last August (so, wipe off a few months…he was 47) when he busted his ankle performing a 30-foot wire-rigged jump for Iron Man 3′s climax, leaving worried cameramen wondering if his reaction was some freakish improv they were supposed to film (Downey frequently insisted they keep the cameras rolling to catch his ad libs) and putting a six-week hiccup in production. “I’m going to be 50 in a couple years,” he notes. “I caught myself the last few years losing sight of that because I work with young people and I see [29-year-old Chris] Hemsworth and I relate to that. But then I’m reminded, ‘He is that; you are something else'” (EW).

Downey is fine with the thought of someone else one day taking over his suit. Gwyneth Paltrow, not so enamored. “Personally, I think it would be very hard for someone to step into Iron Man, because it is so Robert,” she says. “You’ve got pathos, you’ve got humor, you’ve got a facility with language and improvisations and an incredible pain underneath it all. It’s difficult to replicate that.”

Pathos. Humor. Zippy one-liners. Pain. That’s what Robert Downey Jr. brings to Iron Man 3, for sure—in spades. Thanks to him and to fast and furious storytelling from director/co-writer Shane Black, the third of the franchise (and possibly the last one featuring the metal-masked hero in solo flight?) is light-years beyond the careless, noisy to-do that was Iron Man 2, and if it isn’t quite as sure-footed as the first film, it’s a heck of a lot riskier—with most of the risks paying off.

“We create our own demons,” begins the hero in a sober, this-isn’t-the-Stark-you-thought-you-knew monologue before the opening credits are even done rolling. It’s a strong launch for a movie centered on a more mature, battle-scarred, post-Avengers Tony. He’s come a long way from bedding cute reporters and embarrassing the world as often as he saved it.

His scars are piling up. His faults and limitations are staring him in the face. Each film to date has shown him making serious strides away from playboy while keeping geniusbillionaire, and philanthropist, but this is the first time we see the charismatic wiseacre graced with real humility (read: the occasional ability to admit he’s wrong). He’s also reorganized his priorities. Love and loyalty for people outside himself have made him stronger and, for all his devil-may-care nattering, more vulnerable. Capitalizing on this vulnerability is the movie’s greatest strength. Forgetting it is its biggest weakness (hello, Act III).

Iron Man 3 also has strong supporting characters, natty dialogue (“Laurence Oblivier”?), clever plot slaloms, and (naturally) spectacular visuals. The soundtrack: another win. Brian Tyler’s more melodic score (conspicuously sans AC/DC) embodies the attitude-adjustment that three movies, a mess of bad guys, and a nuke on his back have wrought for the cheeky egotist. It still sounds like Iron Man, just with a little less “me.”

But back to the supporting characters. It’s rare for the people to outshine the special effects in a $200-million-budgeted action blockbuster, but that’s what happens here. Especially Pepper. Charming Gwyneth has based her performance of Pepper Potts on 1940s heroines: sexy, witty, and innocent. Here she is more feminine and frazzled and lovely than ever (despite her few unfortunate moments as the red-hot, butt-kicking Amazon babe in the over-the-top finale). After three films, Miss Potts is still the lady who saves her tramp.

And Happy, how did I miss you the first two films? You’re glorious. Jon Favreau (who directed Iron Man and Iron Man 2) gave a few tips to Shane Black, but for the most part kicked back and enjoyed his break from the director’s chair, saying that he felt like “a proud grandfather who doesn’t have to change the diapers but gets to play with the baby.” 

Also marvelous is Harley, played by Ty Simpkins, an in-demand youngster who’s been acting since he was three weeks old and who held his own opposite Downey’s frequent improvs. With Pepper, Stark has grown into the faithful quasi-husband-type; with Harley, he’s growing in just the way his own father didn’t, which is how to be one.

Then there’s the bad guys. At first I thought the Mandarin way too theatrical with all the hair and the rings and the gravel-rich voice, but what do you know, he was supposed to be. The twist is delightful. Ben Kingsley is impeccable and hilarious. And with the Mandarin out of the way, that leaves more room for Guy Pearce to shine at his sleekly nastiest. More of this, please. Pearce is at his best when he isn’t a statue of glowing embers and at his scariest when he’s hitting on Pepper—can I order a double helping of that?

Now for the moments that I will call collectively “meh.” And that would be Act III. All the problems show up in the last 30-45 minutes. (Little baby problem seeds are planted earlier in the movie, but this is where they grow big, behave the most badly, and are the least forgivable.) For one thing, the lava-skinned mutants are out of control. Can they ever die? Because if they can’t, I should be a lot more afraid of them than I am, and so should Stark.

And remind me—why do we care about the President, other than the fact that he’s the President? Make the assassination plot more important (who cares about that old oil spill?) or get rid of it. Let Killian focus on Pepper; he’s creepier when he’s cuddling. Speaking of which, I didn’t for one second believe that Pepper was dead. That’d be okay except Tony didn’t look like he believed it either, and the filmmakers clearly expected us both to fall for it. Or at least they should have—that’s my point.

But the real Achilles heel is how the rather bland adrenaline gala  fails to capitalize on the character development laid down so well in the first 90ish minutes. The opening two-thirds of the movie follow a physically, emotionally, and psychologically battered Tony Stark, but the climax doesn’t beat him up nearly enough. There are way too many handy outs. Who misplaced his panic attacks? He gets hot flashes and a racing pulse whenever anyone mentions New York, but not when he’s dealing with the New Yorkest trouble since New York? And how many remote-control Starks does Stark have? His multitudinous costume swaps are too convenient. You never hand easy answers like this to your hero, especially not at the end. Act III, more than any other story chunk, is where you make him fight tooth and nail for every inch.

Essentially, it’s a flashy, lazy firework show. (It’s Christmas, let’s just blow everything up!) The oomphless ta-da doesn’t resonate as much as the earlier action sequences (like the attack on 10880 Malibu Point), nor does it pave the way for the final surprise. What? Why take the shrapnel out now? If now, why not earlier? Don’t get me wrong, I think it’s a genius puzzle to pass off to Avengers 2 (“That’s Joss’ problem to solve!” were producer Kevin Feige’s words), but you have to build a case for it.

“The love triangle in this movie is between Tony, Pepper, and his obsession with those suits,” Feige describes. “Yes, there’s a bad guy. Yes, the stakes are very very high. But the real stakes are, is Tony going to be able to set aside spending every day in that workshop tinkering with the suits in order to focus on Pepper, the one thing that matters most?” Good question, but the answer seems a bit dangerous even for a daredevil and too drastic even for a guy who tends to be all-or-nothing. (Exhibit A: the T-Rex-sized rabbit.) So again, I say: meh.

But overall, yay. “Can you dig it?” (The last song on the album asks me.) Why yes, I can. The thought of Robert Downey Jr. going away (ever) miffs the snot out of me, no matter how graciously he’s prepared to bow out. “I wasn’t involved in the planning of Marvel’s phases, and I’m sure they don’t end with me,” he says. “Probably one of my finest days of stewardship would be discussing the matter with whoever is cast to carry the torch. That’s what life is about.”

Whatever, Downey. You are Iron Man.