Avengers: Endgame: how Tony Stark used his old armor flaws

Avengers: Endgame (2019), starring Robert Downey Jr., Chris Evans and Mark Ruffalo, gave Tony Stark a heartbreaking send off. It did so in a way that was true to every side of his character, including how smart he is. In my view, the whole of Endgame is a tribute to how brilliant Tony has been at adapting his tech, battle after battle, over the past decade.

Tony doesn't only work out the missing link in the other Avengers' time travel technology. He also has the sharpest recall of the details inside historical timelines, coming up on the spot with a backup time and place to retrieve the Tesseract and more Pym particles. Even more ingenious, he uses tiny details from past generations of his own Iron Man armor, specific forgotten loopholes in his upgrades, as weaknesses he exploits against his past self to get the upper hand.

Iron Man adapts his suit in small ways to respond to past mistakes, from Afghanistan to Spider-Man: Homecoming

Go back through Endgame and all of the MCU movies with Iron Man and you start to notice specific things about the evolution of Tony Stark's suit. In each movie, Stark adapts the technology in small ways to respond to mistakes from previous conflicts. We first see this adaptive thinking in the original Iron Man, during Tony's trial and error montage as he customizes each component of his armor. That experimentation never stopped. It evolved all the way through to the present.

In the first Iron Man, Tony was kidnapped in Afghanistan with no GPS for anyone to track his location. So later, in Spider-Man: Homecoming, Stark reveals to Peter Parker that the suit he designed for him comes with a GPS tracker. When Peter asks whether he put a tracker on his suit, Tony answers, "I put everything in your suit," and that includes a heater.

That heater was an adaptation from Stark's own past as well. He iced up during his test flight in the first Iron Man, and in Iron Man 3 his suit lost power in the snow in the middle of Tennessee. The parachute that pops out of Peter's suit is another adaptation, this time from Rhodey's War Machine armor in Captain America: Civil War, months earlier. Rhodey dropped out of the sky in that suit and was nearly killed, and that lesson comes back again further down.

Electricity and the arc reactor were the weak points of Stark's early armor

One of the more memorable moments in the first Avengers movie comes when Iron Man fights Thor, and Thor's lightning accidentally supercharges Tony's suit to full capacity. Remember that the previous time we had seen Iron Man, he was fighting Whiplash in Iron Man 2, and that earlier generation of armor was particularly vulnerable to electrical damage.

The biggest vulnerability of Stark's early armor, though, was the arc reactor in his chest. He had it surgically removed at the end of Iron Man 3 and threw it into the ocean, where it probably plugged a whale's blowhole. Before that, his mechanical heart was a major weak point, most of all when Obadiah Stane paralyzed Tony and yanked the reactor out of his chest.

How Tony uses his Mark 7 armor's flaws in the Endgame time heist

That brings us to Tony's brilliance in the time heist. Tony knew that the 2012 generation of his armor, the Mark 7, was still powered by an arc reactor embedded in his flesh, something that could send him into cardiac arrest if tampered with. Stark also knew from his experience in Civil War that the tiny openings between the pieces of his armor were wide enough for Ant-Man to shrink down into without being noticed.

Stark fixed that flaw with the nanotech armor revealed in Avengers: Infinity War. Its tiny bots lock into place seamlessly, without any cracks for small things to slip through. Back in 2012, however, the gaps were still a vulnerability. So present day Stark uses those old design flaws, the gaps in his armor and the fragility of his old arc reactor, to let Ant-Man paralyze his past self so they can snatch the Tesseract.

Stark also knows that the Mark 7 suit won't be damaged by an electric shock from Mjolnir. So a little love tap from Thor could bring his past self back to life.

From the Hulkbuster to the Mark 50, Iron Man fixed what failed in Age of Ultron and Civil War

Avengers: Age of Ultron brought two big upgrades. The first was the Iron Legion, which led to Ultron and ultimately to Vision, the first derivation of Stark tech that could contain an Infinity Stone. The second was the Mark 44, the Hulkbuster armor. In Age of Ultron, the Hulkbuster's repulsor blasts weren't powerful enough to restrain the Hulk. So when Infinity War begins, the new Mark 50 armor has backup boosters to blast Cull Obsidian, the member of the Black Order with a build similar to the Hulk's.

The Mark 50 armor is awesome. It has new flight stabilizers, shown during Iron Man's fight against Thanos on Titan, to control his flight during combat, which is something he had trouble with before. It also has rocket boosters on its feet that give him super flight speed, so he can catch up to Peter on the alien ship. He installed those after he failed to catch up to Rhodey during Rhodey's fall in Civil War.

Civil War left another lesson. Tony lost to Cap and Bucky in their melee at the end of that movie, so in Infinity War the Mark 50 armor comes with new melee weapons, which Stark uses against Thanos.

The Mark 85 energy shields answer the Power Stone blast from Infinity War

One of those melee weapons in Infinity War was a shield formed out of Stark's nanotech pieces. The blast from Thanos's Power Stone wore down those nanobots, which caused the nanobots on the rest of Stark's armor to relocate and weaken the suit.

Stark adapted this for his latest armor in Endgame, the Mark 85, which has new external energy shields. He fires them up to brace for the impact of the blast when the Hulk snaps with the Stark gauntlet.

The Stark gauntlet is Tony's most critical adaptation in Endgame

That gauntlet is Stark's most critical tech adaptation in Endgame. Back in Age of Ultron, Stark learned that an android body derived from Ultron's Iron Legion tech could house an Infinity Stone, which is how Vision was made. Now Stark has expanded on that foundation to recreate Thanos's Infinity Gauntlet as a unit of his own design.

This Stark gauntlet has one key feature: nanotech. Infinity War showed how those nanobots can morph and reconfigure into new shapes. There's a subtle visual detail where Stark takes off his sunglasses and they're absorbed into his nanotech armor as it assembles around him. The sunglasses were nanotech too. If you think about it, Stark didn't need to take them off at all. He took them off to look cool for Ebony Maw.

That absorption function gives Stark his key move over Thanos at the end of the film. During the brawl on Titan, Stark was unable to claw the gauntlet and the stones off Thanos's hand, and he came so close. That must have driven him crazy over the years. So with his new Stark gauntlet, the nanotech lets his armor absorb the stones onto his own hand.

Tony Stark's sacrifice completes a decade of tinkering with the Iron Man armor

Stark's sacrifice was such an emotional gut punch because we know he achieved it by finally perfecting the armor he had been tinkering with year after year. He's "the ultimate weapon builder finally crafting the ultimate peacekeeping tool."

That story arc is memorialized at his funeral, where Stark's first arc reactor, framed by Pepper, is placed on his wreath. And for anyone who stayed through the end credits of Endgame, the sound of Tony hammering in the cave echoes once more, a reminder that Tony Stark's obsession with constant innovation and adaptation is what made this engineer the ultimate MCU hero.