The Unknown Soldier is a cinematic epic as well as a Finnish film classic. Though I have never read the original novel its easy to see why many Finns find it so compelling. Also, generally as a film it is an extremely strong example of what Finnish cinema is capable of.
The movie is a grade-A example of a good war-film, that doesn't rely solely on gruesome imagery or battle footage, but is interesting because of its strong characterization. The characters in deed are the most memorable part of the movie, despite being somewhat over-blown. The over-all tone also varies nicely, between light-hearted humour as well as extremely bleak imagery.
In all the film has only two major weaknesses. First the slightly dragging narrative responsible for the over-all length of the film as well as occasional lack of authenticity. But even with these weaknesses the film delivers a powerful message.