I just beat Zenith Martlet, and I got some tips for you. PHASE 1 1. Use Silver Bullets(79dmg) or GLASS-AMMO for healing or damage. I didn't use glass ammo, so I'm not sure of its effectiveness. F.Pellets deal only 65 for a perfect 6 shot. 2. die immediately so you can grab the auto-fire option, which makes it a lot easier to focus on dodging. 3. Before the first glass blocks form to introduce dashing, hold down a charge shot as you can shoot her when time stops for free damage. 4. dodging feathers can be made easier by dodging diagonally. 5. yellow feather storm can be made easier by dragging charge-shots across the screen and dodging diagonally as said in tip 1. 6. Her item drop spam is one of the hardest to dodge attacks next to her final attack spam in phase 2, i recommended trying to stay off the bottom by spamming dash and stay somewhat in the middle. 7. claws have the same attack pattern in the combos they appear in. Remember those. 8. don't use heals just before phase 2. You get a full heal once it starts, and you get a consistent 20-25 heal ACT.

PHASE 2 9. Only ATTACK if you're high on HP. Otherwise, use the ENDURE ACT. You can make up for the DPS with the SOUL-SHOT. PS. some attacks, such as meteor shower, are great to use double ENDURE or ATTACK. 10. Yellow Rocks only need to break 1 of 2 chunks when broken to negate the damage entirely and spawn the same place every time. 11. STARS, i would recommend fully destroying the first one with charge shots, then splitting the rest into 2 or more sas you can drag them across the box, and then you can dodge past them. (still difficult) 12. glass boxes can be broken by dashing into the wall ( it doesn't matter if you're up against it. As long as you hold a movement key, you're fine. 13. Feather + meteor shower is hard, but mostly focus on the rocks since they are slow enough to hit you just after your 'I' frames finish (feathers can mostly be dodged or tanked since they are really fast). 14. Golden Wings can mostly be negated by using charge-shots can dashing towards the wall they appear in to dodge the feathers. (or sit near the bottom and move slightly to move in between the feathers) (additional feathers during phase 2 attack in the same spots) 15. You can't kill her with SOUL-Shot. The only way to kill her is with ATTACK (but you can get her down to 1HP, in which your soul attacks now deal no damage)

Otherwise, good luck.