Before sending anyone to see it, you need to warn them that it violates not only political correctness, but also the Hollywood script writing conventions, acting conventions and editing conventions. The dialog is adapted from writings of the period and is completely unlike anything heard in movies today. There are no fast cuts in the editing.
Big ditto! They patterned the dialogue on letters and speeches, not actual vernacular. The director should have spent some more time looking at letters written by common soldiers. They actually used cusswords and expressed emotions in a language the modern reader could identify with. The movie included too many quotes from marble monuments to allow the story to carry itself. The director focused on the minutinae of the Civil War instead of telling a coherent story about whatever he was trying to convey with way too many side lines from indistinguishable bearded men.
The reenactors did okay, but didn't portray the gore of a Civil War battle accurately. A real CW battle rivaled the opening scenes of Saving Private Ryan in terms of horror.
GAG has all the hallmarks of a 30 minute history channel documentary. While I appreciate the noble effort involved in this movie, it was still a bad movie by any standard. Being politically incorrect and having a positive depiction of Christianity does not a good movie make.
If anything, Civil War buffs should be disappointed in this movie; the financial losses it reaps will insure there are no epic Civil War movies for some time to come.