NES Party and SNES Party are sites that do a think that would have seemed like magic 10 years ago: they make it easy to pick out NES and SNES games, load them into the browser from the Internet Archive, and not only let you play them yourself but share a room link with another person and enable internet-based multiplayer. It’s all as simple as that.
Well, mostly. When I tried using it, emulation was much faster than normal. The game load screen suggests, if this happen, that you reduce the refresh rate of your display, which seems like kind of a kludgy solution. But on the plus side, snes.party has Rampart!
NES Party and SNES Party