I'm far from an expert player, but I really think the physics are identical once the patch is in place. I sometimes wonder if it was really a mistake at the factory—something they didn't catch until 20,000 PCB's in, and didn't want to change in revisions for consistency.
> The actual mechanics behind the issue were discovered a while ago (the Y-reverse thing isn't right). Something to do with the block getting replaced immediately instead of a one-frame queue/delay.
Unfortunately I can't find a fuller explanation for this claim.
Having used the patch, it does feel right...
Maybe brick-blocks taking an extra frame to swap from tiles to sprites for their animations, was something perceived as an unfixed bug (or a necessary compromise, due to per-frame CPU-time limits) at the time of the original's development — one with, perhaps, a "TODO" comment sitting there in the original assembly source. And the development team of the port noticed that, with either more dev time, or with the increased cycles-per-frame available on the SNES, the "bug" was able to be "fixed".
But perhaps — since that team wasn't aware that the change in physics this created was unexpected by the original devs — they thought that the physics resulting from "fixing" this "bug" were the originally-intended physics of the game (i.e. that the animation "bug" was a regression, and fixing it put the game back the way it was in some earlier build), rather than that they were introducing a regression themselves.
These sorts of things are the reason I've always wished version control got used more heavily in the gamedev industry back in the 80s. Then any leak of a game's code-base would actually have a productive use (rather than just serving as poison fruit to aspiring developers): it could be a treasure-trove of data for Software Engineering academics to study the in-industry SwEng practices that lead to "good" games vs "bad" ones.
(I've had a longstanding hypothesis that many "bad" games from the 80s/90s were "good" games for much of their development, but got broken very close to release as they tried to merge in tons of longstanding feature-branches — i.e. the exact problem Continuous Integration tries to address.)