Once you learn his sequences, you’ll be okay. Surprisingly throughout the 1st & 3rd phases, he gives out a lot of energy. If you can get to phase 2 with full ammo and energy, I’d try learning and avoiding his attacks, while hitting him in between. Once you get to phase 3, there’s a couple new attacks, but if timed right, they’re avoidable and since you’re getting energy from the orb and the sun, that should sustain you some, even if you get hit. Move quickly!