Nice looking minigame expect for player suddenly changing into that square, you can prevent that from happening you know (might require assembly but can be done likely with pure scripting though)
I've a similar script in my own hack (which is Gen II one) in which the graphics of another person are copied to VRAM (Video Ram) so that they replace the graphics of the player that are loaded before-hand when you enter to that room. This happens so that the script is called right after the sprite graphics are loaded to VRAM but the screen still stays black/white because not everything that happens in that map are loaded yet. You could try to do something similar to that if possible.
Looks good though, can't deny that
Not a major glitch though but makes the hack look somewhat unprofessional if not corrected.