The boss has one attack, a spin flamethrower that doesnt stops, every fight is just a sidestep shooting, also, sometimes the dragon spawns outside the screen, So you cant see whats happening.
Adding simple things to the game like a :"Reload time" to the boss, Changing the spin direction , More patterns, Changing the color of the dragon after each respawn , and making that the dragon spawn inside the Screen will make the game way better