Idk how to make it work but what I was trying to do was make it so that when the player touches either side of the border or the side of any platform, it goes the opposite way. I can't seem to also add jumping properly to this mechanic and it's just a hot mess. (I was also aiming to make it so that when the up arrow key is pressed and the player touches the side of a platform [or a side of the border] that the player can do a little wall jump OFF the wall, not the kind of wall climbing generally used in platformers.
