Cataclysm DDA, if it counts. There's usually a lot of time between stable releases, and by the time they come out, it usually feels like a completely different game.
CDDA, takes awhile to get comfortable with the controls, but it does scratch a certain itch once one can get setup and start to test one's luck in search of the good stuff.
One has to make their own objectives for it though otherwise one can sort of just get to a point and not know what to do. But getting to a point where you can just walk into a city and be the most dangerous thing there does have a certain charm to it considering the journey getting there. It certainly rewards exploring though as one can find all sorts of craziness hidden away waiting to be found.
Kerbal Space Program
Voices of the Void, slow horror
A gaming community free from the hype and oversaturation of current releases, catering to gamers who wait at least 12 months after release to play a game. Whether it's price, waiting for bugs/issues to be patched, DLC to be released, don't meet the system requirements, or just haven't had the time to keep up with the latest releases.
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