W A S D to move. Space to attack. Dodge the boss and it's projectiles. It will start shooting projectiles faster as it switches phases.
Credits to Calamity Mod devs for the boss and weapon sprites, and YouTube channel Miki Hiroyuki for the music. If you didn't like it, tell me why! I can't improve it if you stay silent about it. Known bugs You might have to click the flag twice to get rid of the death/win screen. Hard AF in the last phase.