The Witness is a masterpiece. It blew me away when I played it the first time (I just started another playthrough of it last night too). Although now I have since played The Outer Wilds, and I think it does something that feels similar to The Witness, but executed it a little better, despite being a different game. The world building is a lot stronger in The Outer Wilds, and it's more of a technical achievement, and it a lot more tense and dangerous.

Although I do think Jonathon Blow successfully dug into and found just about every single possible interesting puzzle you can make with moving from a dot and drawing a line through a maze to the end, including some really crazy things that most people wouldn't think of and wouldn't be possible if he didn't create a giant world for those puzzles to live in.

> Stardew Valley

Has now multiplayer (CoOp based).

So not useful to meat new people but can be used as a platform to hang out with outer people you already know over the net.