Sometimes these featurettes would just be regular TV episodes cropped and blown up to widescreen 35mm film, but (despite what Anime News Network's encyclopedia page claims) this is not one of those, it's an original Starzinger story not shown on television.
The torrent is here. Direct download link is here. (fixed)
EDIT: Also, here's an easter egg for people who visit my site: the trailer for the movie can be downloaded here.
Dog Soldier Volume 1, with Hokuto No Gun and Illuminati-Manga - Have we got a freaking treat for you...From Tetsuya Saruwatari, our three groups have teamed up to present you with Dog Soldier, the tale of John Kyosuke...
49 minutes ago