Lohengramm, with his vast ambitions and Yang the reluctant soldier form an interesting contrast. They're almost the polar opposite of each other, but in many ways they are similar. There's a sense that the two men are destined to become great rivals, and what makes the movie fascinating is the anticipation it creates for the future.
Yang and Lohengramm aren't the only characters seeded in this prelude who have future significance. If you come back to this after watching a portion of the series, you'll find plenty of other important characters lurking around, but most of them don't have much of a role to play, so it's unlikely that you'll have taken too much notice of them first time round.
As a movie from the 80's, it shows its age quite clearly. Everything about the movie less than polished. Yang's initial characterisation feels a little heavy handed. In their attempt to portray him as an easy going fellow, they went too far and ended up dehumanising him a little. His overly nonchalant demeanor means that he seems less than bothered by the loss of so many lives during one of the battles in the movie, and it feels like he barely regretted his lack of effort towards its prevention (being marked out only by a single casually delivered line).
Another gripe I have with this movie is how incompetently they abused the use of classical music. Normally, making classical music work with the scenes seem trivially easy - rarely do I come across instances where people messed it up, but this movie somehow managed it, and in a manner that's comparable to "Mars of Destruction" (I've probably just landed myself in hot water with the legions of LoGH fanboys with that line, but I stand by what I said :P). The makers' idea of good music production seem to be to start playing a long, random piece of classical music (presumably one favoured by the director) when a battle begins, then just leave it to run its course, giving themselves a self congratulative pat on the back for a job well done. This shockingly lazy approach only resulted in battle scenes that are jarringly devoid of tension and excitement, and a movie where the use of classical music comes off as awfully pretentious.
The battles themselves aren't bad. There are some strokes of genius to be found - the battle at that planet being one such example - but there are also parts that seem to be reliant on the somewhat far fetched stupidity of the opposing commanders, a fault that unfortunately extends and amplifies into the main series.
But as far as preludes go, "Legend of the Galactic Heroes: My Conquest is the Sea of Stars" is a decent one. The movie may not be amazing, but it does promise far more interesting things are to come in the series it's preluding, which is its main purpose anyway.
