Outer Wilds is a pyramid scheme.

Once you play it (or see someone else play it - don't do that if you haven't yourself), you can never play it again. As a result, you will want to recommend this game to everyone you know just so you can have someone to talk to about it. You will watch countless play-throughs of the game to vicariously experience it again. It's a pyramid scheme, but everyone wins.

Aside from that, this video game is the best piece of art I've ever engaged with. It's poetry in motion, with themes that weren't completely clear to me on my playthrough, but evoked emotions I didn't know I was capable of. Only on watching other people play it have I come to form opinions of what this game is really about, but I think it would be inappropriate for me to discuss that here, where people who have not yet played might read it.

Do yourself a favour and play this game.

(Aditionally, the DLC might as well be a full sequel. They just crammed it into this game. It's of equal quality and adds a deep richness to original game that it never really needed, but works so well with.)