Thanks for playing! The title song is actually just the instrumental for Bae's song DROWN if you want to vibe to it without booting up the game.
To get the good ending you need to get all the items (essentially a "full armor set") and then answer all questions correctly. In general, you should pick the ones that feel more "hopeful" if that makes sense, and there should be 5 questions you can answer. Missing any item, or doing the puzzle incorrectly, makes it so that for the corresponding question you don't get a choice and she just goes "..."
Yeah the boss is fight is pretty hard, but that's on purpose. She's beatable, but it does require a strategy and a bit of luck lol.
The neutral ending, which I assume is the one you got, is if instead of attacking Bae, you do nothing.
Anyway I'm glad you enjoyed it!