I’m a big fan of choosing between an assassin or tank and then describing the abilities you have! I also like how you describe the setting and feelings after we obtain these powers. However, a piece of feedback I have is about the boss fight. I was caught off guard when I saw the two options:
"Trust your discipline and strike in complete harmony / good ending
Surrender to the wild, unchecked rage of your power / bad ending."
I suggest not straight up stating that one option is the good ending and the other is the bad ending. This will push most players to pick the good ending instead of choosing the other option. Removing those labels would help keep the suspense because the player wouldn’t know which choice will lead to which outcome. It would also keep you immersed in the story instead of reminding you that you’re playing a game and choosing between a “good” or “bad” ending.
