-Wait by the pit and hit the parrot when you see it fly towards you. After hitting the parrot three times, the bridge will appear. Go across the bridge and use a jumping high slash attack on Marrow. After hitting Marrow five times, the parrot will pick Marrow up and fly to the opposite side of the screen. Immediately jump up to the platform and wait for the parrot again. Keep repeating this strategy.
-With at least 25 bullets, start on the pit and pull yourself back until you are touching the wall where the door is supposed to be. Crouch every time you hear Marrow shooting. Try to shoot him back as you crouch, but try not to expend too many bullets. The parrot will make a different sound each time. Be ready, as it will fly straight towards you. This is when you should shoot it. Hit it three times, then the bridge will open. Once it is set, jump onto it and stay in the middle. From there jump towards Marrow and make an aerial slash (sword attack while jumping). Right after doing it, and while still on the air, pull yourself backwards again to the middle of the bridge. Repeat this until you have hit him five times. This must be done four times before he finally dies. Note - When attacking him, try not to jump too high or he will most likely shoot you in the head. Also, do not get too close to him; always chase him in the distance and stay on the bridge when attacking him.