I defeated Queen Stingra in normal difficulty, love Bob, hate capitalism. That was great as I played several small sessions and during this last longest one I never got stuck at the end of a wave which would never end, don't know whether it's because I was more cautious and tried to kill the enemies fast or if it's unrelated, either way I had got a bit frustrated the last time but this time it was extremely pleasant.
It was super cool. It's very pleasant to control and feels great, due to punchy enemy bullet patterns (like the drone turning and launching his strong and fast round pattern, that's super catchy) as well as strong feedbacks especially when you get hit, it feels sturdy which really sets the feel. There're diverse enemies all proposing their own threat (the queen uses quite some patterns which is cool) and the difficulty of the game was perfect for me (I died once on Wave 10 on hard, and a couple of times around that one on normal). Finally the unstability feature is great in part because I sometimes wasn't sure of what happened which makes it better (for example during my successful run I got the screen covered in brown just when reaching the queen so I am not 100% sure whether my rage got attacked instead of my hp at the end due to unstability or the queen which does fit the theme super well, and when you get thrown into the corner of the screen, shaking, without the moving commands responding it's just perfect too).
Since waiting lowers your rage meter then maybe you should have no control over when a wave ends, waiting before defeating the last enemy shouldn't be allowed, thinking about it I think the remaining enemies should actually leave the screen at some point so you don't get the money.
Great game!