Nice game!
Some feedback:
1) There seems to be two builds of the game in the ZIP file. "Flappy KFP" and "Kotori's Adventure".
2) When going into Pause by clicking the pause button onscreen and then going back into game by pressing ESC, the pause button remains focused, so if you try to fly with SPACE, the game goes into pause again.
3) I use an ultrawide screen, so I can see when the next set of obstacles spawn on the edge of the screen. Obviously that's not supposed to be visible on a regular 16:9 screen. Maybe try adding black (or your preferred color) pillarboxes to cover the sides of the screen outside of the expected visible area, to keep the game in 16:9.
4) Sometimes the drumstick is counted twice. I couldn't reproduce the bug consistently to figure out why it's happening. My guess is the colliders involved are calling the scoring method more than once.
5) I suggest you add the "Hololive" tag to your game to make it more visible in the search.
Good job!