Having seen both the 4-episode OAV version of Armitage III and the Armitage III Polymatrix DVD, I note some interesting differences between the versions. Particularly interesting is the fact that the Polymatrix cinematic movie version was done _only_ in English, and subsequently subtitled for Japanese viewing--that's how the Japanese wanted it. There is no corresponding subtitled version of Polymatrix; it's an English-only film.
Polymatrix alters the storyline of the OAV series slightly, cutting a few scenes and adding a bit of new animation. It also adds two new voice actors, replacing the OAV dub cast: Kiefer Sutherland and Elizabeth Berkley as the two leads. For the most part, these cuts are acceptable; they improve the pacing of the movie at the cost of some additional story and characterization. While I was watching, I hardly missed what was cut. (For those who are concerned with seeing the whole story, the four OAV episodes should be viewed, preferably in the subtitled versions.) The ending is also changed slightly, and seems to me to make more sense in this version.
The storyline of Armitage III is set on a colonized Mars, and concerns itself with a new third generation of robots ("Thirds") that can actually think and create. A madman by the name of Renee D'anclaude has found out about these Thirds and is going around killing them. What is less clear, and somewhat confusing even when it is explained late in the movie, is _why_. It took repeated viewings of the OAVs, then finally the movie itself, for me to figure out the full political motivations behind the murders--and why it was that the Thirds stood in the way of an important political treaty between Earth and Mars.
Although Armitage III becomes somewhat confusing in the last twenty minutes, it nonetheless is an interesting and thought-provoking movie that should not be missed.