Continuity mistake: In the scene where John Basilone goes looking for his friend Manny. Basilone has 3rd degree burns on his left forearm and left hand but in the shot he is walking through the jungle holding a pistol tightly in his left hand and his canteen is on his right side as he walks past a group of trees. The next shot he is continuing walking through the jungle but the gun is in his right hand (which isn't burned) and his canteen has also switched sides as he walks past the same group of trees.
Continuity mistake: When we see the guy trying to open the coconut with his bayonet, his blade is either on top of the coconut or digging into the coconut depending on the shot. (00:21:20)
Continuity mistake: When Jay realises he pooped himself, his M1 Carbine rifle is on the ground. In the next shot when he looks up to tell the other soldiers what happened, you can see the barrel poking out from the bottom of the screen.