FMJ rip off
In my opinion this is like the Full Metal Jacket. In FMJ, the basic training part in the beginning has nothing to do with the action in Vietnam. And it was by far the best part with Lee Ermey's ad lib performance.
Same thing here; Omaha beach assault is the best part far and away, but had nothing to do with the rest of the plot (which is unbelievably lame).
Spielberg is not quite the genius movie guy he is made out to be. He clearly stole an idea from FMJ.