Use your mouse to move and dodge black. You will auto-fire up, but you can change that direction with left and right arrow keys (or a and d). You have 5 hp, and each time you get hit, you will take 1 damage and have 2 seconds of invincibility. Every time a bullet hits the red, it will take 1 damage. It starts at 400 health, and you must knock it down to 0 to win. You lose if you run out of hp. The blue and pink enemies have 40 health each. While they are alive, the boss will not spawn more clones of them (so there can only be 1 blue and 1 pink enemy at a time). Press space for hardcore mode (1 hp). Press p for practice (100000 hp, 4000000 boss hp. Just practice without constant dying)
Tell me if you find bugs. It definitely is possible (and possible not to take damage), but considering it is a hard mode of my hardest bullet hell shooter so far...