Thank you very much for your kind attention!
I tried to play it again in the browser version.
This time I tried with only one heart, one bomb jump, and grappling for the ability increase.
It was a very hot battle with tons of enemies coming at me!
It looked like I could attack with no damage if I dropped bombs from above with bomb jumps, but I sealed that battle strategy halfway through because it seemed to be too easy.
But after thinking about it, it might have been fun to challenge the boss with my initial status since I could proceed without taking power-ups, meow~!