70's Robot Anime Geppy-X

Geppy-X is a 2D side-scrolling shoot-em-up developed as an affectionate parody of the 1970s super robot era of mecha anime pioneered by Go Nagai and Ken Ishikawa. In it, you play as a super robot fighter squadron in an alternate universe 1970s, fighting against alien invaders from the Space Devil Empire.

The titular robot has three transformations all modeled after famous 1970s super robots, as well as a super form known as Geppy-XX.