First the positive. Some excellent period battle scenes. While events seemed to be lost on them, the weaponry, and chaos that is battle was captured beautifully. If you are a re-creationist or just a history buff interested in warfare from that era this is a must see. Forget the rest of the forgettable movie and just watch the battle scenes and enjoy the rich landscape scenes that come at times. Excellent camera work and cinematography. The choreographing of the battles in terms of scale and weapons was first rate, though the hand to hand combat tended to be weak and one sided.
Now for the down sides.
While they got a few things correct. There was a battle. The French were overconfident. It did rain and this probably saved the Mexican army. Many of the names were correct. Pretty much everything else was wrong, Even for Nationalistic propaganda which this film clearly was, casual research would point out huge historical gaffes.
Few of the actors should give up their day jobs.
Much moralizing against the French, yet the opening scenes portray acts of brutality by the Mexican army. Ironically I doubt the people who made the film even realized it. Especially given the years of brutality which followed the departure of the French.
The French were portrayed overly harshly. While the French were not known for being gentle, especially in that era, they were not all monsters as portrayed. Then again this is a Nationalistic propaganda piece so this is to be expected.