Galaga and Galaxia, plus most other shmups, have vastly smaller hurtboxes than this game though. Not as small as bullet hell games, sure, but still way smaller than this. I used to play shmups and bullet hells, and I've definitely played shmups/BH games easier than this.
Half the reason this game is as hard as it is is because the player hurtbox gets absolutely gigantic in the later sizes. The other half is because the game's super cramped, I wish the dev would extend the screen up a bit and make it a vertical game screen ratio like a lot of the vertical shmups out there.