I have an old Raspberry Pi 1 (!) still going strong with Batocera Linux running NES, SNES and Mega Drive (Genesis) emulators.
I’m looking for easy multiplayer games that can be played with a 5yo. Non violent and ideally co-op, bonus points if somewhat educational.
This is the way.
And in case OP doesn’t know: the same can be done with Sonic 3 and then with Sonic and Knuckles.
But also, I second starting with Sonic 2. The controls are a bit simpler, and it’s a classic.