Larry is holding the jug of bogus rocket fuel when he falls through the laboratory floor. In the next shot, he falls into the jail cell below, but he is not holding the jug.
When Vernon Dent first places the medal on Philip Van Zandt he pins just under the medals already on Philip's uniform. Later when Vernon removes the medal from Philip, its lower on his uniform.
When Shemp picks up the jug of fuel from the jail cell, it's nearly full, but when he brings it outside, it's nearly empty.
When the guard's head gets stuck in the jail cell, the bars move freely when he moves around.
When the Stooges are pulling Shemp through the floor while the general is trying to pull him up, it is obvious that a dummy has replaced him in several shots.
When the boys make their escape in the jeep you can see someone standing on top of a store front balcony .