Tetsuo and Tetsuo II - classics of their domain (the first one more so) have been transferred from high-resolution source material, supervised by Shinya Tsukamoto (creator, director and actor) himself .
Unfortunately for humble DVD viewers (like myself), the high-definition transfer has to be downscaled back to our simple 576p (or thereabouts), and one side-effect of this is that the image is softened; a gentle blur, if you will. The grain of the original is still there, but somewhat softened. For quality purposes, this is a much better outcome - an easier image, no sharp edges, etc.
I can't help but feel this detracts from Tetsuo though - to me it's about being on a videotape, or camcorder-filmed; rough, dirty and raw.
The discs are split oddly - extras being the second disc, and both films being on the first - although this is merely a superficial complaint, the quality is fine.
Blu-ray viewers may find more of the raw visual elements which have been filtered out of the DVD version, but for the movies alone - I'll stick with my original releases.
Extras include trailers and the 45-minute "electric rod boy" movie which led Tsukamoto into the Tetsuo realm. A collector's treat, but if you can get it on Blu-Ray, the real treats will come in the films themselves.