There's something fishy going on here - the HK Blus of the first two "20-seiki shônen" films were certainly not reference material, but this one looks really bad, like upscaled SD, and crappy at that. Compare e.g. the following shot from the 1st film with its counterpart in the 3rd one (note the jagged edges of the box in the latter):

Here, the shot from the 2nd film seems to be a little jagged too, but the overall blurriness all but hides the fact. The shot from the 3rd film, though, looks awful! :-P (You'll notice more of the jaggedness in the gallery below.)

UPDATE: I found some screenshots from the Japanese BD edition of the film on the Internet - as suspected, they confirm the HK Blu is really messed up: