ooh yeah, through the subway tunnel right? I figured that was hard enough to do that I wouldn't have to worry about anyone doing it, but I see you've proved me wrong. I'll add some wall or something there in the next update.
I was trying to find surf (still haven't found it) so I decided to check through there.
Update: I FOUND SURF!!!!!!
What's surf?
The cerulean tunnel glitch is the easies one to do.
