There may be more issues, I haven't played at 60 FPS that much: I played the entire thing at about 144 FPS (it wasn't steady); a friend pointed out that I should probably play the game capped at 60 FPS and I just tested it out to confirm. I think doing everything related to game logic in `_physics_process` should do the trick but I have never actually verified that. I'll just play the other games at 60 FPS from now on.
Looking forward to the update!