Avengers: Endgame delivered a monumental conclusion to Marvel’s Infinity Saga. The Russo brothers crafted a narrative that balanced intimate character moments with universe-spanning consequences, allowing heroes like Tony Stark (Robert Downey Jr.) and Steve Rogers (Chris Evans) to complete their arcs in emotionally satisfying ways. In addition, the film masterfully wove together narrative threads from 22 previous movies while delivering unforgettable moments: from Captain America finally wielding Mjolnir to the iconic “Avengers Assemble!” battle cry to a battlefield of portals opening to reveal resurrected heroes. These powerful payoffs, combined with genuine stakes (established through permanent character deaths), created an experience that resonated deeply with audiences and critics alike, resulting in an unprecedented $2.798 billion global box office haul.
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While Endgame succeeds as an emotional spectacle, its introduction of time travel and multiverse mechanics created several logical inconsistencies that become increasingly problematic as the MCU expanded into the Multiverse Saga.
Here are three fundamental logical problems in Avengers: Endgame that remain unresolved years after its release.
Thanos’s Plan Makes No Ecological Sense
Avengers: Infinity War presented Josh Brolin’s Thanos as a complex villain driven by ecological concerns rather than simple megalomania. His mission to eliminate half of all life followed a twisted but consistent internal logic about resource preservation. When showing Gamora (Zoë Saldaña) the results of his “mercy” on her homeworld, he points to children with “full bellies and clear skies” — evidence that, in his warped thinking, justified his actions. By then, it was also heavily implied Thanos targeted half of all sentient life by manually killing each world’s population.
Endgame undermines Thanos’s characterization through specific scenes showing the Snap’s devastating aftermath. The five-year time jump reveals a broken world rather than one experiencing ecological recovery. When the Avengers first visit the Compound post-time-jump, the establishing shot shows dark, gloomy skies and eerily still waters as visual cues signaling environmental degradation. Most tellingly, when Bruce Banner (Mark Ruffalo) reverses the Snap, birds suddenly appear and begin singing outside, confirming that Thanos eliminated half of all wildlife, not just sentient beings.
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If Thanos truly destroyed half of all living things, as these scenes indicate, he decimated the very ecological systems he claimed to protect. The disappearance of half of Earth’s plant life would immediately reduce oxygen production. Even if plants were excluded from this calculation, and we add only animals to the effects of the Snap, Thanos’s plan still makes no sense. The loss of half of all pollinators would devastate agriculture far beyond losing half of human farmers. So, rather than doubling available resources per person, the Snap maintained exactly the same ratio of consumers to resources while destroying the infrastructure needed to use what remained. Not a great plan for a universal utopia.
Captain America’s Time-Travel Return Defies the Established Rules
The time-travel mechanics in Endgame are explained through Bruce Banner’s convoluted exposition, where he states that traveling to the past creates a new future while the traveler’s present cannot be changed. This establishes a multiverse approach where changes to the past create branch realities rather than altering the original timeline. However, by the end of the movie, Steve Rogers is tasked with going back in time to return the Infinity Stones to the exact places where the Avengers have removed them.
Steve’s mission contradicts the MCU’s rules for time travel, as Steve’s return to the past would not fix the branches created during the Time Heist. Instead, it would only create new branches. The film never addresses this fundamental problem, treating his mission as if it could somehow repair timeline disruptions rather than create additional ones. Even more problematically, the appearance of an aged Steve Rogers in the final scene indicates he went back to the past, aged naturally, and is now an old man in the present. Since the film clearly establishes that going to the past creates new branches, the aged Captain America should not be in the Sacred Timeline at all.
The Ancient One’s Decision Contradicts Her Knowledge
When Bruce Banner travels to 2012 to retrieve the Time Stone, his conversation with the Ancient One (Tilda Swinton) reveals another fundamental inconsistency in Endgame’s approach to time travel. The Ancient One initially refuses to relinquish the Time Stone, creating a visual demonstration showing how removing an Infinity Stone would create a dangerous branch reality where “millions would suffer.” This establishes her deep understanding of multiverse mechanics and timeline protection.
However, her decision changes after learning Doctor Strange (Benedict Cumberbatch) willingly gave Thanos the Time Stone in the future, leading her to relinquish it based on Banner’s promise to return it. This directly contradicts both her established knowledge and the film’s time travel rules. According to Banner’s own explanation, returning the stone wouldn’t “fix” the Ancient One’s timeline but would instead create yet another branch of reality. By the film’s established logic, the moment she gives up the Time Stone, her reality becomes permanently vulnerable to the very threats she used the stone to combat, like Dormammu.
The scene presents a fundamental paradox: the Ancient One either doesn’t understand multiverse mechanics, or the film’s time travel rules are inconsistent. As keeper of the Time Stone and guardian of reality, the Ancient One should have recognized that Banner’s promise couldn’t actually protect her timeline according to the very rules the film establishes. Her sudden acceptance based on a solution that doesn’t work within the film’s own logic represents a significant oversight that prioritizes plot progression over narrative consistency.
What other element of Avengers: Endgame still makes no sense? Let us know in the comments!
