Jiro Hitoyoshi's character is a throwback to Jiro, the main protagonist of Kikaider. Not only do they share names, but in episode 3, he's seen playing an acoustic guitar, which is what Jiro from Kikaider is always seen carrying on his back. Jiro Hitoyoshi is also seen playing guitar on the album cover of Concrete Revolutio's soundtrack.
Both ending themes have individual title cards for each character, in which they present the characters in action. This is a callback to the unit director, Norimitsu Suzuki's, other work. Notably his work on the ending themes of UN-GO, Soul Eater, and Fullmetal Alchemist from studio Bones, which feature similar traits.