Revealing mistake: When El Mariachi's one friend first fires a rocket at the bad guy's limousine in the climactic battle, you can see that the rocket itself never explodes, despite the side of the car blowing up. The rocket simply lands next to the car, and then remains there in plain sight whilst the side of the car blows up, revealing that it is just a prop replica.
Revealing mistake: When Bain is in the bath and communicating with his employer, you can see he is just punching random keys on the keyboard that do not match up with what he is supposedly writing. First, he writes "Nothing. I retired the buyers", but he never touches the "n" or "e" keys. A little later, he types "And", but his hand never comes near the "a" key. (01:07:10)
Revealing mistake: When Herod shoots Rusty in the back before the final gunfight, a car can be seen driving down the road in the background.
Revealing mistake: After the XO orders all stop, we see a close-up of the ship's yoke being pulled back. The next wide shot shows the interior as the bow of the sub is rising, and just before this shot ends, note the console that the man with headphones is working at. A pair of crewmembers cross paths in the foreground, then the entire console wobbles, proving it isn't attached to the floor at all. (01:09:00)
Revealing mistake: Near the beginning, when Westlake is experimenting and his mask melts, you can clearly see that the mask is not really melting, and is just covered with suds while a "melting" sound effect plays.
Revealing mistake: When McCord climbs to the top of the arena he fights with a guy patrolling the rooftop. He then kicks the guy over the edge, but the way the guy falls back shouldn't have sent him sliding down the roof.
Suggested correction: He pushes the guy with enough momentum to slide down the roof.
Revealing mistake: When Kinjo is fighting Saito, he throws away his sword and fights Saito with his bare hands. During the duel, he first slams Saitos arm over his knee, then elbows him in the side of the head. But look at Saito's head; he reacts to the elbow LONG before it connects.
Revealing mistake: At the start of the film, Sergeant Gunn and another member of his tank crew take shelter in a shell hole as they are returning with fuel and spare parts. Watch the supposedly dead soldier hanging over the edge as they leap into it - he visibly reacts and moves his head.
Revealing mistake: When Dwight is falling down the stairs, you can easily tell that it's a (much older) stuntman.
Revealing mistake: The mix of two shots is obvious such as the photographer inside the centerfold's top.