Thanks for playing the game! I really appreciate all of your feedback. It helps the development of the game even more. The music was composed by my friend, JPSoundWorks.
For now, the optimization is still a bit janky, and it needs a lot more work to stabilize the framerate. I'm going to do my best to improve the use of this 3D plugin and the action battle system. Maybe in the future, I'll add more RPG elements to enhance character progression.
Regarding the room after fighting the boss, did you try going forward to the stairs? It is supposed to lead you to the ending of the demo. If it gets stuck there, I should probably fix it as soon as possible so players don't miss the important plot point at the end.