I understand your criticisms, and can work on addressing them. Moon Man's stage is experimental, and I don't doubt it needs a redesign.
In regards to Reactor Man, I can see why you'd feel that way. I'm able to beat him without taking any damage, but I've played against him so many times so I have the moveset needed to beat him memorized. I've thought about doing a complete redesign of his moves but never committed to it. Your comment might be the impetus I needed to do that.
I'm glad you enjoyed fighting Glacier Man. He's in my top 3 favorite boss fights in the game. His moveset is simple but fun to play against. How do you feel about the other bosses?
Anyways, really appreciate you playing the game and leaving detailed feedback. It means a lot to me.