Yes, very old DOS-based games from before 2000 can be emulated perfectly. If you have a modern computer, even the later SVGA 3D games running in protected mode are no problem (using 100–200k cycles/ms in DOSBox).

In fact, today’s graphic possibilities and available monitor resolutions make it possible to accurately and aesthetically simulate an analog CRT monitor with its scanlines and aspect correction (DOSBox Staging). But of course you can just use big sharp pixels.

That makes total sense for eg DOS/gameboy/arcade games and the like, but is it ever that simple for PC/windows games? And there are many different issues that I have experienced when running older games myself, even if they can technically run, eg with ultra-wide and higher dpi monitors.

What I also like in this project is that they also share logs with what they worked on each game, eg for the resident evil series [0]

[0] https://www.gog.com/blog/resident-evil-1-2-3/#:~:text=RESIDE...

Not only is this a sensible idea, it's also just a fancy way of running in an emulator like you would for another game.

Now I'm wondering if you could put e.g. a Windows virus into a Gameboy game, such that if someone did the opposite of what we're talking about and ran it "natively" then they'd be infected. Afaik this kind of native execution as an alternative to emulation is being done via recompilation projects - see e.g.

NES - https://andrewkelley.me/post/jamulator.html

N64 - https://deepwiki.com/Zelda64Recomp/Zelda64Recomp/3.1-recompi...