I've seen that emulators are running the game on PC at 60fps.
But I was surprised to see that there's also a build of the game running natively on PC.

I'm just wondering how that happened? Don't they need the sourcecode for the game, or reverse engineer it?

I feel like we see console games running natively on PC very rarely, and decades after release.

And actually, how come there are already Switch 2 emulators? That also tends to take at least some years.

AI has completely blown emulation wide open. I can't say much more than this, as I'm not fully informed on the "How?" component, but I do know "AI vibe coding" has allowed for these emulators and decomp projects to be up and functioning no problem.

Yeah, game decompilations/emulation has progressed very rapidly with the use of AI.

I hate the technology myself and have been keeping myself away from anything involving it, but there is some sweetness in seeing it be used increasingly for purposes of piracy. Companies and their billionaire CEOs are only now starting to realize how this thing they've been pushing down our throats might come back to bite them.