Thanks! I went and watched your stream. I was rooting for you and felt dismay when you and the audience reasoned that the batteries would disappear if you defeat all of the bad guys! If you hit them enough times, they disappear and you can collect the motherboards.
That's great feedback about the character's falling and gravity level. I don't know anything about the programming side of things, but yeah when I have played these kinds of games, the physics of the jumping feel about like what you described. Come to think of it, the hardest or most frustrating part of the boss battle for me was the feeling that I was suspended or floating in air--felt like I had no control while I was being shot at.
Thanks again for playing!