The #1 goal of that movie was to entertain, not show historcial fact.  Take it for what it is, drink a beer, and relax.
Yeah, I watched the movie and in the back of my mind I nit-picked bits and pieces but ultimatly it wasnt that bad, it was a real spitfire/109/P40, etc that were in the air and not com CG imagage, be glad for that.  A BAR, a shotgun, a few bolt action rifles, etc are not going to bring down a fast moving zeke, etc.  LOTS of drama stuff.  But again, it is a hollywood movie, not a historical drama.       
The BoBros series if the best yet, imo, when it comes to realism and war.