That is bizarre. Its the first time Ive heard of this and I cant reproduce it myself. Try restarting the game using the ROM and a GBC emulator and see if it happens again. No one else has mentioned this bug so I'm not quite sure what to make of it. I'll keep investigating.
Well I restarted my computer and hence my game data and the bug is still a thing. I am unsure as to how to use an emulator sorry 😭
But I mean. If the bug only causes ME problems, it ain't that bad. I just can't finish the game XD I'll still try my best but I've been stuck and hour on the double bubble jump to fight Mum. Not being able to run and jump to the left makes it hard lmao 🤣
I found the Issue! I was using the Z key to jump, ya know, cause it's the correct one. But actually, for SOME reason, the J key also allows me to jump. And for an even MORE confusing reason, jumping using J allows me to run and jump to the left. I have NO idea why that's happening but hey! I finished the game so yay :D
(Also, did musky rat survive? I hope he did T-T. Poor boi needs some headpats!)