Being pretty much ignorant of Temudjin's early years, I was free to enjoy the movie without prejudice, although, when the boy warrior survived enough privation, accident, and hostile action to have killed a normal boy six times, I began to suspect we were getting into the realm of legend. (There is some veiled implication of divine intervention--.) However, checking up later, I was surprised to see how much of the movie did follow what is generally accepted about his early life, including the death of his father, and usrpation of his position. However, in typical movie fashion, several clans/tribes that were in opposition at verious times get concatenated into one (the Merkits) and Temudjin's family life is likewise streamlined (extraneous brothers are never mentioned, for example). The movie timeline ends at the year 1206, at which time Temudjin had succeed in uniting the the Merkits, Naimans, Mongols, Keraits, Tatars and disparate other smaller tribes under his rule, was acknowleged Khan, and first took the title of Genghis.
The movie is a distinctly multinational production, with Russian direction, German financing, and a host of other nations represented, which may account for the casting of Japanese actor Tadanobu Asano as the adult Temudjin. Asano, according to IMDB.com, is considered a cross between "Johnny Depp and Toshiro Mifune" in Japan. Although he does a good stalwart hero, I didn't find his breadth of acting to be all that inspiring. (I note that Asano also played the hired samurai bodyguard Hattori in the 2003 "Zatoichi" film, a distinctly Mifune-esque type of role, but I found I had totally forgotten him in it.)
Actually, we found the actors who played the main characters as children, Odnyam Odsuren as Young Temudjin, and Bayertsetseg Erdenebat as his wife-to-be, Borte, more interesting to watch than their adult counterparts. Both these kids are in their first movies (probably not a lot of work for child film actors in Mongolia) but have lots of potential. Odsuren particularly jas lots of screen time, and is a tough kid if he does his own stunts--.
That being said, the adult Borte, Khulan Chuluun, is interesting to watch also, and does a good job of being tough and resourceful when needed, and frustrated when her husband leaves her home with the children again while setting off on another years-long warpath.
There is a very good supporting cast as well, chiefly Honglei Sun as Jamuka, Temudjin's blood-brother and eventual rival, and Amadu Mamadakov as the villainous Targutai.
Another main star is the setting, ranging from the Gobi Desert to mountains to the steppes, at once beautiful and bleak. The moviemakers take advantage of the landscape, using it to shoot an old-fashioned epic with minimal digital effects (only in evidence in the climactic battle scene).
Of course there are a lot of battles, and, unfortunately some of the verisimilitude is a casualty of the movie-making process. In one fight, we see Temudjin and his men hunkered down behind a makeshift barricade, bows drawn. In the next shot, Jamuka's forces are storming the position at hand-to-hand. I suspect something got lost on the editing table here. In the big battle, Temudjin demonstrates innovative tactics by having fifty or so heavy cavalrymen cut through ten times their number of enemy lancers using something that can only be described as a horseborne version of the scythed chariot maneuver. Looks unlikely on film, and even more unlikely in the real world--. A lot of battles result in a lot of blood. The directors tried to be artistic about it, but it seems that every saber-cut comes from up sun, so that the (inevitable) spurt of blood turns to a glittering spray of ruby. Nice, but it pales the third or fourth time you see it.
These are nits to pick: overall the movie was very enjoyable and worth seeing if the subject matter interests you. Rated "R" for violence, (hardly any sex), so leave the little Hordesmen at home, no matter how well they might fit right in--.