Other mistake: If the bullets from the super gun move at just under the speed of light, how come the bad guys can't hit him or the girl? The bullets would arrive almost instantaneously and that would mean minimal compensation for them running. Plus the guy had them locked on when he shot.
Other mistake: When Arnold and Vanessa are in the dead guy's office running the CD, Arnold pulls up the shipping date for the arms deal. The screen shows the date to be "TODAY" and Arnold says "Midnight Tonight." Midnight would be 12:00AM, so the screen ought to read 12:00AM tomorrow morning, not today. (01:22:00)
Other mistake: When Arnold lands on the car in the junk yard, you can see the side windows of the car exploding outward moments before impact. (00:57:10)
Other mistake: In beginning of the zoo scene, Cullen shoots J. Scar in the leg and he collapses in pain. For the rest of the scene, he pursues Cullen and fights as if nothing was wrong with his leg.
Other mistake: After Kruger tosses the parachute, there is a quick close up, and it looks like the chute just got tossed from another plane. Also, half the time, the chute has dust or smoke coming from it, and sometimes not.
Other mistake: After Kruger throws the chair into the engine causing it to explode, the co-pilot starts to hit switches overhead. As he does, the panel shakes, like it is a poorly constructed set. If it were real, the craft would be grounded until the defect was corrected.