This movie is certainly best viewed with the knowledge that it was made during the Stalinist era and only just before WW2. Eisenstein has a knack for creating jarring, interesting images (such as the skeletons in the opening shots) but this is also simply a fun film to watch, and one that unabashedly does everything that the Soviet censors of Stalin's time could possibly want from a film; it's a lot like how how most Hollywood directors nowadays make really similar types of films to please their producers, only it's interesting to see what was considered "popular culture" at the time of Stalinist Russia.
In case you don't know the story, it involves the Novgorod Russians (Novgorod is a city far north of Moscow, considered to be one of the major foundations of the Russian civilization) fighting against the invading German Teutonic Knights in 1242. The film does not attempt to portray this part of history as it WAS; rather, it is portraying history as it SHOULD HAVE BEEN (at least from the point of view of the Stalinist era). The Teutonic Knights are unabashedly evil, throwing Russian babies into raging flames and throwing evil glances from under dark cloaks. Also, they all look and speak Russian (in contrast to post-WW2 Russian films, where Germans usually spoke German). The Novgorod Russians, by contrast, are unabashedly heroic and valorous, "we must free the Russian soil!"
The characters in this film are really secondary to everything else, but for the first while this doesn't hurt the film since it floats by on interesting images and events (did I mention that the costumes are wonderful?). Later on, the middle of the film does get a little bit boring; the lack of good characters might be hurting it, or perhaps Eisenstein was running out of interesting things to show us. There is a love triangle involved, but don't get too excited; how it will turn out is so predictable from the very beginning that I found it pretty funny.
The highlight of this film is probably the battle sequence with the Teutonic Knights. Not because it's a realistic, insightful depiction of battle - no, quite the opposite. The battle is accompanied by a happy, drum-heavy Russian tune that makes you want to shout "Glory to MOTHER RUSSIA!!!" to honour the sheer absurdity of it all. The Russians gleefully hack away at the Teutonic Knights with their blunted swords (it's not hard to tell that they're blunted; obviously they wouldn't use REAL swords), shouting things to each other while single-handedly fending off Knights that remain just beyond the range of the camera. Of course, there are lots of overhead battle scenes as well, although these are problematic because you can tell that they're not really fighting that seriously.
The real highlight of the battle scene begins when the Russians gain the upper hand and begin chasing the Knights accross the icy lake, all to the beat of that happy march music that was playing before. The whole scene is like a long comedy, and is pure fun to watch.
After the battle is over, there IS a period of mourning for the dead, but it isn't allowed to last too long before the movie's inadequetly-developed characters have their happy endings.
All in all, a fun movie to watch, although it is very obvious that it is (a shining example of) a pre-WW2 Stalinist-era propaganda film. Post-WW2 Russian films are VERY different in outlook from this one.