I've tried for about an hour now and I can't get it to work, and since I know people have noticed that there are some control differences, I'm wondering if Nintendo "fixed" this?

I assume you mean the one in World 3-1. Yes, it works, but as with the original you can exceed 99 lives and turn the digits into garbled symbols.

It took me a while to do it, but then I kept going for too long and got the garbled symbols. Dying once with the symbols gave me a Game Over. Something about the controls or the emulation or the alignment of a blue moon on Tuesday makes it much harder to do than on a NES (for me at least).

EDIT: Well, never mind. I got it again, only kept going for about 5 seconds, finished the level, and got garbled symbols. When I died, it wasn't an instant Game Over like before. Hmmm...

Hm indeed. I personally can't even get the sequence to start, but I've never been able to get it to work on the NES version. Why on earth would they try to prevent this?

It does work but for some reason it seems harder to pull off in this version. On an actual Nes I can do it easily.
There was definitely something causing it not to work well. Maybe I'm just not timing it right.

I'd assume the glitch would be intact; they kept the Minus World, after all.