The concept of being able to switch between doors you hit is can be great material for level design, but i think you should be able to exorcised door with the projectile.
Unfortunately I'm not able to finish the first level, it seems not possible to reach the door inside the tower, sorry if there was more..
Some hitbox issues, you have invisible hitbox, it's not easy to know what block you, and you can get outside of the map falling in the void.