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.
Lots of other great suggestions. But I do think the consensus is multiplayer games with coop.
Konami beat ‘em ups like TMNT, The Simpson, Xmen would be great.
I’m also going to throw in Party games or kart racers, CTR and Mario Kart of Mario Party or Crash Bash would also be great
That said Pokémon might be a nice option too though not sure how you’d play that together.
Or edutainment like Gizmos and Gadgets or Jumpstart
Sonic 2.
Controlling Tails can be good fun if you’re very young and don’t fully know what you’re doing!
Can be hard keeping both characters on screen at times though.
Actually Sonic 3 is a slight improvement in this regard once you get the hang of things - Tails can be more helpful, and carry Sonic to higher ledges
Gta 1.
Super Mario World, Battletoads
Magical Quest 2 & 3 are very good for that. They already know the characters, and the games are beautiful and pretty good gameplay-wise.
You play together and if the child loses all his/her lives, he/she can steal yours. For difficult sections or bosses, you can do it alone.
There are new costumes regularly so the child wants to continue to discover the next costume, and its associated powers.
Magical Quest 2 is easier than 3, so I think it’s better to start with this one. You can either play as Mickey or Minnie.
In Magical Quest 3, you can either play as Mickey or Donald. Donald is meant to be played by the child because his gameplay is a bit different (with his soldier costume which is wooden barrel, preventing him to sink while Mickey has a silver armor which kills him if he goes into water with it). It’s not that difficult to play as Mickey (my nephew did not want to play as Donald and we had no major issues).
Goof Troop, for SNES.
Oh, and sorry for so many responses, but I figure that posting these separately will let the votes give you some idea where to start.
The votes I’ve seen so far very much reflect the order I would try these games out with a five year old gamer.
Fun-N-Games (Genesis/Megadrive) is mostly single player, but has many mini games accessibile to young gamers.
It’s single player, but too good to miss: “Richard Scary’s Busy Town” (Genesis) is a fantastic open ended set of mini-games that are fun and accessibible to almost all skill levels of gamer.
Ms. Pac-Man (Genesis) is fully co-op throughout, and has adjustable difficulty by choosing smaller maps.
Mega Bomberman (Megadrive) and Super Mega Bomberman (SNES) both have multiplayer mode where players can team up against bots, and the bots have adjustable difficulty (different bot skins have different AI).
I was going to recommend Bomberman. Super Bomberman 4 on SNES in particular is very fun, you can grab not only bombs but opponents too, and there are cool mounts with special powers. A bit chaotic in some arenas, but the classics are still there of you want them, and then when everyone gets better ot wants a quick laugh, you can go for the crazier ones.
Dashin’ Desperados (Genesis/Mega Drive) is a racing platformer, where the adult can control the difficultly by slowing down or backtracking.
Super Baseball Simulator (SNES) is competitive, but can be really chill if the adult player throws easy pitches, and the super powers are hilarious.
“Toejam and Earl: Panic on Funkotron” (Genesis) has a very well designed “little kid mode” in the options, and it’s still really fun.
World of Illusion (Genesis)