Revealing mistake: When Wade gets shot, watch the shot where Upham brings the bags up to the injured medic. The next shot there is some fog which then reveals the injured medic. In this shot, watch carefully as the cast rips away the medic's shirt. If you look near the neck, you can see the fake stomach vest he is wearing for a split second - when the actor realises he ripped too far up, he quickly covers it back up. (01:28:43)
Revealing mistake: When Alain is holding Guido's dead body and telling Steinkampf that he "died as a Legionnaire", you can see Guido swallow if you look at his throat.
Revealing mistake: During the scene in which the small group of GIs, led by the young go-getter officer played by John Cusack, attack the Japanese hilltop bunkers, they seemed to be equipped with magic bullets. The American soldiers are firing wildly in all directions but seem to drop an enemy soldier with every shot. In some shots, the GI's rifles are not pointing even near where the Japanese soldiers are but the latter obligingly fall dead nonetheless.