Jinzou Ningen Kikaider The Animation, Concrete Revolutio: Choujin Gensou Recommendations
Very similar animation, character design, and story telling. Concrete clearly pays homage to Kikaider in several ways. In an early episode the main character of Concrete (Jiro) is seen acting quite a bit like the main character of Kikaider (also Jiro). Both characters were unaware and/or rejected their true natures and had a lady helping them accept it.