Other mistake: When the TV reporter is talking about the men in green being killed, she says dead bodies were found all through the city, at night. However she was reporting on the 7 bodies found (with the appropriate graphic). According to the newspaper, the 7 bodies were found by police in the morning, in one dumpster. Plus, we know when a thug killed a man in green he or she brought the body in, so they weren't found throughout the city. (And she wasn't reporting on bystanders being killed since she mentions they were all wearing green).
Other mistake: When the captive begins her escape, she kicks the bed through the orange portal offscreen, but the portal only starts about a foot off the ground, so the bed would have hit the wall, rather than have gone through the portal.
Other mistake: When Bishop kills the arms dealer while Steve McKenna looks on, he stands behind the guy and in one quick motion, rips off the belt cleanly from the guy's waist, then he strangles him with it. There is no way you could yank the belt off like that if it were buckled. And even then, the buckle is certain to snag or rip one or more belt loops before you can pull it off.
Other mistake: At the beginning, the arrival board has the cities listed in alphabetical order, but "San Francisco" comes after "San Jose" when it should come before it.
Other mistake: Between the freeway battle scene and the convenience store scene; there's a transition shot where you can see the characters walking through a bombed out LA with the alien aircraft flying above. If you pay attention to them, instead of following the camera, at the end of the shot you will see them all stop moving mid-stride while everything else in the shot continues to move.
Other mistake: Just as the preacher finishes stitching up Jake's wound, a shot rings out from the street, and everyone goes outside to find Percy Dollarhyde drunk and shooting up the town. Percy is right-handed but holsters his 6-shooter revolver on the left, and this appears to be his only sidearm. Even if he did carry another 6-shooter, that wouldn't explain how he fires 13 shots in this scene without reloading.
Other mistake: Towards the end during the last fight with Zeus, Atom is following Charlie as a mirror - when Charlie moves his right hand Atom moves its left, etc.. At one point in the last round Charlie jumps and punches with his right hand, but Atom hits Zeus with its right too.
Other mistake: When removing the car from the penthouse the guys decide to use the crane portion of the window cleaner's lift. The basket disappears without trace, what did they supposedly do with it?