On the multiplayer side - Eco. An incredibly underrated game. You have a month of playtime to extract resources, develop your society, and be advanced enough to stop an asteroid. Leaving minimum impact is heavily encouraged, and it has the most sophisticated economic system I've seen in any computer game.
This, I have joined a small server and it is just a good game.
I went in expecting it to have "cringeworthy levels of hippy idealism", but no, it is actually a reasonably sane game. It is the first game since Wurm Online that I have felt like part of a community thanks to the game mechanics themselves, and not just incidentally. A lone person will need inordinate amounts of time to go far into the tech tree, so instead people specialize, and soon after I was running a delivery company that moved orders of resources between players, with people greeting eachother when passing by at the trade district.
Not really, the game is really made for the "10s of people scale".
But thanks to how it works, it doesn't need 10s of coordinated people, you can certainly just join some existing server with a friend and have an equally good time.
This was my biggest annoyance with Eco. It really does take a community, which is disappointing because you can't scale it down to 1-4 players. Are there any mods for this?
They've recently revamped it so you can adjust various levels (skill increase, cap, multipliers, etc) and make it possible to play with fewer. I've actually run a couple of single-player games, completely vanilla. Fun in a different sort of way.
It has a base setting for something like "1-3 players" that's pretty quick, and there are some advanced settings with which you can make things "cheaper" -- both in time and in resources -- via some coefficients.
I also "cheat" at the start by using vanilla commands to research and level up in all the disciplines -- makes the game more about finding and efficiently utilizing resources without also having to scavenge random stuff to "research". Since there's such a breadth of everything, it reduces the grind ("specializations" are annoying if you're forced to be a jack of all trades) without making it too easy.
It still feels like a real accomplishment to build a large building -- both architecturally and via thinking about how each block traces back to the resources pulled out of the ground -- without requiring huge amounts of time in the game. I'm fairly proud of this one [1], and more so of the industry and infra that supported it.
Plus, Eco is just gorgeous, especially when in single-player with low ecological impact there are so many animals hanging around all the time (peep the alligator in that shot).
IMO with a low total player count, a lot of the more interesting mechanics in the game go completely unused, even if you add multipliers so resource gathering is conveninent time-wise. No point in using the shop system with just 3 people, let alone the government stuff. So while I'm sure you can fiddle with the numbers, it just won't be the same experience.
