Just watch it on DVD, 11 years after it was released. Tezuka was not keen for Rintaro to make an anime of it before his death in 1989. Rintaro dropped the idea until he talked to Otomo (who eventually wrote the script) in the 1990s and Mad House studio got involved in the animation as well.
The villain, Rock, also appears in other Tezuka manga - eg. Phoenix Vol 2. Part of the Tezuka Star System.