About half-way through the movie (43:59), Sergeant Mooney decides to go and see his commanding officer, Captain Trelawny, while outside is heavily raining. However, when Sergeant Mooney exits the bombed-out house and walks into the street, the weather is bright and sunny.A few minutes later,Sargeant Mooney returns to his squad in the bombed out house and he is soaking wet while outside is raining (46:14).
When Lee Marvin calls Pvt. Collucci to be look out using binoculars. If you listen you will hear Jets fly over during WWII.
When the group attacks the machine gun position with a mortar, Pvt. Muller holds the mortar tube with his bare hands. After the first shell is fired that mortar tube would be as hot as a cast iron skillet sitting on a hot stove. No way he could continue to hold it with his bar hands.
When Pvt. Collucci throws a grenade at the German machine gun, it is easy to see where the grenade lands as a small puff of dust is visible. However, the explosion occurs well to the left and behind where the grenade actually landed.
About a minute in as Pvt Coke ducks into a building through a wooden door, two bullet holes can be seen in the door. The scene cuts to a sniper's rifle barrel. When the scene cuts back to Pvt Coke at the door, the bullet holes are gone until the sniper shoots the door.