SPOILER WARNING: this list takes a deep dive into some of Infinity War's most ill-advised details. Proceed with caution.
By now, you’ve had time to digest Avengers: Infinity War, so you've probably realized it didn’t make a whole lot of sense. After a long string of successes, Marvel was bound to slip up at some point, and unfortunately, Infinity War is a convoluted mess. The reason why Infinity War is the worst Avengers movie cannot be reduced to a single moment, as the film is plagued by a series of bizarre decisions that collectively create a feeling of disorder.
A few critics who caught the film's midnight premiere left the theater exhausted and filled with Infinity War critiques, and the negative buzz has only gotten louder as fans have had time to seriously reflect on the sprawling mess. A lot of people are left with unanswered questions about Infinity War, and judging by the myriad plot holes, creators are seemingly okay with leaving things unexplained. While it can be fun to turn your brain off and watch actors smash CGI aliens, once you try to make sense of what's happening on-screen, it’s hard to ignore how flagrantly Infinity War missed the mark.
Thanos is the big bad of the MCU, so he has to exist in multiple storylines, and the easiest way to get him back and forth is to have him teleport. His ability to be wherever he wants makes him a huge threat, but it also forces viewers to wonder why other characters' teleportation powers only work when it's narratively convenient. Doctor Strange and Wong have abilities similar to Thanos's, but there are several key scenes in which they seem to forget this.
Wong even manages to cut a guy's arm off with his powers, so his inability to do the same to Thanos is incredibly frustrating.
One of the biggest plot holes in Infinity War comes after Thor shows up on the Guardians' ship, gives them some info on Thanos, and says the villain is going to Knowhere to look for the Soul Stone. Gamora happens to know where the stone is, and says she needs to stay as far away from Thanos as possible to keep the location a secret. Then she goes to Knowhere.
The plot requires Gamora to wind up in Knowhere, as she needs to be captured by Thanos, but that's not good storytelling. If there had been something driving her collide with Thanos, it would have made more sense, but as it stands, she voluntarily elects to do the exact thing she said shouldn't happen.
Aside from his position as franchise antagonist, the story of Infinity War provides little explanation for why Thanos wants to wipe out half the galaxy. In a flashback, Thanos says he watched his world die from a lack of natural resources, so he decided to kill half of everything, leaving the rest to prosper. It seems like it was a tough call to make, but he figured the surviving half of the universe wouldn't mind, and felt the Infinity Gauntlet was the only way to accomplish his task.
The thing that trips up a lot of viewers is, once Thanos acquires the Gauntlet and all of its Stones, he never considers using it to create additional natural resources, instead of murdering everyone. Josh Brolin portrays Thanos as an intelligent villain who believes he's doing the right thing, so it's odd he never reflects on his own ability to change reality to fit the needs of the galaxy.
At one point in Infinity War, someone asks where Scott Lang (Ant-Man) is, and Black Widow says he's on "house arrest." This begs the question: why doesn't the appearance of a crazed, universe-bending titan who wants to wipe out half the galaxy temporarily override a superhero's house arrest?
According to one of the film's directors, Joe Russo, Ant-Man and Hawkeye had to be absent from the film because "we have a really interesting story cooked up for both of those characters, and part of that story required that they be under house arrest." While Russo may be correct, that doesn't make the moment any less of a retcon.