The idea of repeatedly fighting a random permutation of the same boss is very appealing. You learn the boss’s movement and attack patterns, and so to some extent your experience is transferrable, but you still have to learn and adapt! Conceptually, it’s inventive, and your boss design is just as creative – I love how you can anticipate its movement patterns based on the placement of its jets.
The visual feedback for hitting the boss is crystal clear, and this could be enhanced further with some juicy sound effects across the board. I also find that the reloading mechanic is just a timed task – in lieu of simply unlimited bullets, maybe the player slows down to reload, so you have to pick your window carefully? Either way, nice work!