If you are playing it in your browser then it is being distributed, unless you have some sort of stadia, play via video type service, then, to get all sorts of pedantic "this is technically legal" the owner would have to have to make sure no more than then the number of legal copies of the game were played at once.

Personally I don't worry too much about a bit of copyright infringement, especially in cases like this where there are no plans to ever publish the title again.

like archive.org?

Pretty sure the emulators there run locally, so it's of dubious legality.

They're a library. Their ability to serve binaries isn't dubious.

Last I checked you can download permanent copies of old roms on archive.org. I don't know how that's legal, I've always assumed it was just that nobody cared to DMCA any of it. I'm fine using it, but if you're being a huge stickler for legality I don't think it's clear.

They have a DMCA exemption: https://archive.org/about/dmca.php

Nothing in that article suggests hosting ROMS for download is legal. Said article states the original media is required for the exemption. Hosting ROMS does not require the Downloader have the original media.

Nor does archive.org have any special "exemption".

They have an exemption to the bypassing DRM rule on software, not one stopping DMCA takedowns.

Thanks for researching this.