Minor Plot hole: Although the fight scene between Tom Cruise and the Burj Khalifa is one of the best cinematic rivalries of recent times, there is no way it would have worked. The reason? Glass. Glass Everywhere. Ethan climbed up 11 floors at the speed of a drunk turtle - which means dozens and dozens of people would have spotted him outside and alert security guards who could have ordered a taco on the first restaurant floor and still being on time to catch him when he reached the server room.
Major Plot hole: Michael Nyqvist was probably surprised when he read his part and realized that his villainous role in the movie would be spent 50% running away in chase sequences and 50% surviving catastrophic accidents that no one on Earth can survive.
You see, Hendricks is presented to us as a cerebral villain, a man with a 190 IQ who does not have a super combatant background. Naturally, the movie then shows us Hendricks surviving a terrible car crash in a sandstorm that made his car flip like a 3000 pounds pancake and then outrunning Mr. Top Gun himself like the million dollar man 2 seconds later. What? Oh and landing on his head after a 10 story fall doesn't instantly kill him either. Don't worry, you can see him again next year in the upcoming movie Freddy vs Jason vs Hendricks.
Major Plot hole: I'm not done with Hendricks. Remember when I wrote that he survived a 10 story fall by landing on his head ? (I hope you do - this was 3 lines ago, focus). Well he didn't have to jump. His plan was just to buy enough time for the countdown to reach zero before Ethan could reach the briefcase and stop the nuke. For a 190 IQ man, it is rather imbecile to not consider simply throwing the briefcase on the first floor WITHOUT the rest of his body attached to it. Hendricks would have survived and secured his chances of succeeding by fighting Ethan again if he reached the briefcase at the last few seconds.
Major Plot hole: I'm not done with Hendricks. Remember when I wrote he had a tough guy on his side to do most of his dirty work ? (It's a trick question, I didn't). Well he does have a henchman - but for some reason decides to go to the Burj Khalifa himself, pretend to be his tough guy Wistrom with a super-high tech mask - only to be later picked-up in a car by the real Wistrom. Why ? Is there any reason to do something like this ? Is an excuse even remotely shoehorned-in to pitifully try to convince us it makes any kind of sense ? (SPOILER ALERT: no)
Super Plot hole: Hollywood continues to keep military tension in its various narratives by pretending we are still living in the 1960s. Technology has evolved a lot since the first potential nuclear war between superpowers. Are we to believe the United States would not have done anything if Ethan Hunt did not stop the nuclear missile from arming itself before hitting San Francisco ? As of right now, you could lunch dozens of nukes on the United States.....and they would all be intercepted midway over the Oceans. Are we to believe that the United States has no concrete plan to stop ONE nuke from hitting their country? Not only did they not intercept the missile before it crashed on American soil - they also failed to spot its presence. In short, if the United States was accurately shown as not being run by morons (at least on nuclear threats issues) Hendricks's plan would have failed without Ethan Hunt's intervention - so there you go, there is no movie.
Plot contrivance: We all tried to rob a bank or a Russian military safe-house at least once in our life - they don't call them teenage years for nothing. As I am sure you all remember, opening a huge metal safe door is a bit tricky - not only because it requires to bypass a lot of security measures, but also because it is a HUGE freaking door and as all huge freaking doors can tell you: they make a lot of sound. You can't open a 1000 pound door without making everyone in the next room stop talking and wonder who ripped the biggest fart heard to man. But obviously, the Kremlin safe's door right next to a Russian guard makes absolutely no sound when it was opened. Not a single click from the locks either. Your own closet makes more sound than this door!