Getter Robo
"Shin Getter Robo vs Neo Getter Robo" draws heavily from Ken Ishikawa's manga "Getter Robo Go". An anime adaptation of Getter Robo Go was made in 1991, but bore no relation to Ishikawa's manga aside from sharing the titular robot and pilots (who were very different in their personalities and backgrounds). Neo Getter Robo features much more faithful versions of Ishikawa's characters, but with a new plot and new Getter.