This game has a lot of fun enemy designs, doesn't it? The protagonist design varies a bit between cover, localizations, concept art and sprite. I thought I'd try something quite robotic since she can transform, otherwise it gets a bit too weirdly contortionist.
Including here a bit of a rare image I think I saved from twitter(?), enhanced and colour blocked to try to figure out how the thing folds together. It was kinda hard to read with just the lines. Might be a rare image from their design docs. Edit: Actually it's the original line art which was seen coloured in (red-blue) duo-tone in the Famicom manual. There's a third, blonde interpretation of the character on another page.
Skin tone is white on the sprite but pink on the ending screen. I think the excellent evocative JP cover was done by Naoyuki Katoh, who also did the Starship Troopers armours and Legend of Galactic Heroes ships. NA cover was a bit bland, but I think the EU one had some kind of Hajime Sorayama -type silver robot on it. Hmm, that happened with Megaman 2 as well, didn't it?
Blue ball guy is Randar/Lander, one of compile's mascot characters. Carbuncle is a better design, but is unfortunately named and useless in the modern age.
Edit: Added a few more figures. Lots of early primitive life kinda stuff in the game. The jumping robot men kinda stand out.