Back whence you came, or possibly not

When you crash through the rocky walls in Angel Island Zone and Lava Reef Zone, they break off into nicely separated rock sprites which then fly off to whichever direction you punched them.

This makes a lot of sense, which is why I was quite surprised when I saw the Knuckles wall in Hydrocity Zone 2 do this:

I thought, surely, this must be a bug. The pieces are flying right back at you! That's when I realized that the simple 2x4 brick walls have had this behavior all the way back since Sonic 1.

It seems only the walls that use this classic mapping layout inherit the backwards-flying behavior. The thick columns in Marble Garden Zone also break off into square pieces, but they fly away from you. The ice walls in Icecap Zone break up into clean rock sprites like Angel Island and Lava Reef, but the pieces just fall off to either side.

There's no moral to this story, I'm just venting.

BONUS CONTENT because I took a pretty good screenshot: the breakable wall object is still present within Sonic 2's code, and has been refactored to work with the dual player system. However, no code to handle player 2 was actually added, so Tails can't break it.

The object is completely unused in the final game, but it can be seen in the Nick Arcade prototype's Green Hill Zone.

In the Sonic 2 mobile remake, they brought the object back for Hidden Palace Zone. Tails can now break it, of course.