I really like the concept of getting bigger over time and having to choose when going to rage mode. It's a good application of high risk high reward. It's a great concept for a bullet hell.
However, past a point, the saws appear and grow too fast and it feels impossible to survive. Maybe I'm just bad, but past 70 balloons popped it's impossible.
Graphic wise, the minimalist aspect is done well. The few sprites go well with the others. The game is completely monochrome. The game feels juicy with the screen shakes and the transition out of the rage mode. But the retro shader is too much. You could maybe do a in-between of with and without.
Overall: fun game but too short due to the difficulty spike.