Nice polished game!
The procedural part is great, well done!
To give you my thoughts:
-I think enemies spawned on me in the harder level, I just had the camera shaking a bit like when you take damage at some random moments and died after less hits than usual...
- I don't say it would be better with a clue on how many hits you can still take, especially since the levels are short, but maybe if you try to make longer levels it would be nice to know?
- At first I had a controller cabled to my computer and the red ball was moving left all the time! Other games did not had that issue so I decided to share it with you. After unplug there was no problem at all ! :)
Good job !