When they are going to the mine with the radio and battery one Private has his insignia correct then it is upside down. After he walks in (the one without the glasses) his insignia is right. Then when him and the other private went to go look out for the sand worms it is upside down.
A female soldier is wearing both "Ranger" and "Special Forces" tabs on her uniform. Females are not authorized to attend either school, thus it is impossible and illegal according to Army regulations for a female to wear either tab on her uniform.
Army officers wear the rank insignia on the right collar and the branch insignia on the left collar parallel to the edge. The captain wore the insignia pointing to the tip of the collar. The lieutenant wore rank insignia on both collars pointing to the tip.
When the soldiers are on the run from the Serpents and the camera pans to the ground (to simulate the effect of the worm chasing them) while the scene plays out you can see the shadow of the vehicle chasing them.
When Eno and Stanley step out of the mine shack to hot wire the truck, a large moving vehicle can be seen in the distance at frame right (they are supposed to be in the middle of nowhere with nobody around).
When they're wandering through the factory ruins in "Afghanistan" there is large, clear graffiti in Romanian.