Wall running woes, part 2

In standalone Sonic 3, the design flaws in the level collision code are even more pronounced than in Sonic & Knuckles. While running on the ceiling, or a wall on the left side, level collisions are completely ignored, so you'll sail right through solid parts of the level. Obviously, this can easily cause you to become irreparably stuck in a wall- er, I mean, watch out for Dr. Robotnik's diabolical traps.

Unfortunately, although otherwise quite welcome, the changes to the algorithm in Sonic & Knuckles caused a breaking change in one of the Competition stages. (left: Sonic 3 alone; right: Sonic 3 & Knuckles)

In Sonic 3 & Knuckles, you can no longer backtrack through the loop in Desert Palace after you cross it. The reason for this becomes evident once we open up the level in SonLVL and take a gander at the collision data:

The loop is comprised entirely of blocks solid from all sides! The only reason the thing worked in the first place was due to Sonic 3's lax attitude while running on left-hand side walls. Changing the collision on the walkway threading the loop from fully solid to top-only would fix this issue.