Revealing mistake: When the villain finishes his 1st appearance in the Pentagon's videowall (with the fake Eiffel Tower on the back), the screen turns black when he finishes his statement. However, when the camera turns to the Army men present, you can see the reflection of the villain's face on the glass.
Revealing mistake: Look for the blatantly awful special effects when the main bad guy is falling into the flames.
Revealing mistake: When Ryback is fighting the grey-haired bad guy in the kitchen, the bad guy is losing and spots a meat cleaver on the counter. When he quickly picks it up, holding it at head level, you can see the cleaver blade wobbling from side to side. An obvious rubber prop.