Minor Plot hole: John Mason can bend a metal coin with a cheap chair but the same coin is hard enough to cut through a thick safety glass.
Minor Plot hole: Bad guys having bad aim with their guns is a cliché we all accept. But this particular instance of bad aim is so bad that it deserves its shameful elevation as a real plot hole. Here it goes: Near the end of the movie, the past U.S soldiers turned bad guys/mercenaries are having a tense internal dispute about using the rockets. Major Baxter is the only one to side with the General and his opinion to not lunch the missiles. He knows he will have to shoot the other soldiers.
He lies to his general saying that he does not agree with him, but then surprises everyone by turning his gun away from the general and pointing it to Captain Darrow instead. Major Baxter is a trained elite soldier who is a mere 3 feet away from his target. He has the surprise advantage on his side and no one raises their gun against him in time when he instead points his gun to Captain Darrow. Then he quickly shoots a bullet that instead of....KILLING HIS TARGET....hits his shoulder. Really Hollywood? Really?
Major Plot hole: Sean Connery's character (Mason) escaped from Alcatraz decades before the main conflict of the story. When they take him back there with a SWAT team in order to get in without alerting the terrorists, he goes through a fire tunnel with timely patterns that he memorized in his youth.
Then, he is able to open a door from the other side to let the SWAT team enter the prison. This means that the first time he escaped from Alcatraz he went through a dangerous fire tunnel that he studied for months......instead of using the door.
Major Plot hole: John Mason should have died at the end of the movie. Indeed, Goodspeed released a deadly gas in the air in order to kill the last mercenary. He was about to die himself until he injected atropine in his heart. The gas contained in one of those green pearls was said to spread over a large territory. But Mason was not too far away from Goodspeed, he even reached his location roughly a minute after the gas was released. Why didn't he die? Because he is Sean Connery.
Major Plot hole: Mason escapes an hotel by pushing an FBI leader over the balcony and hence obliging the other people to help him out instead of running after Mason. There were however other men inside his hotel suite that were eating a buffet. But no matter what those agents were doing, it means that an old man slowly ran right beside them in the hotel room while they were ' busy ' eating the buffet he so intelligently ordered for them. How did they not hear their FBI leader screaming to his death over the balcony? And how could those 4-5 agents not see and stop an old man running in the small room they were in ? Because he is Sean Connery.
Plot contrivance: John Mason has been in prison for about 40 years. He however does not seem to have any difficulty driving a Humvee and operating a car-phone at the same time. Both of which he never saw before.
Plot contrivance: How can an injection stop a compound from melting your flesh? It does not change how your skin is going to react with the deadly gas. But that's ok. Write it in your script and everything will be just fine.
Plot contrivance: Stanley Goodspeed (Cage) is trapped in an Alcatraz prison cell and his begging Mason to tell him how he got out of his cell years before. Mason does not answer and simply opens his own cell's door that clashes against a wall creating a big vibrant sound. Goodspeed however does not hear it because the script wanted him to be surprised when his own door his opened afterward by Mason.