Ruins To Fortress looks like it could be interesting, a post-apocalyptic free-to-play pixel art open survival game. The developers have announced it's going to enter Early Access on December 13th.
Like a sort of blending somewhere between Terraria and Starbound, set on a single island where you craft tools, grow food, build formidable defences, and raze enemy bases. Here though you can either cooperate, or go after rivals so it's more on the competitive side. So perhaps a bit more like a side-scrolling Rust as you'll be able to host your own servers too.
They also have a new trailer to show it off:
Direct Link
Since it will be free they will be offering a single DLC to support the game that will include what sounds like mostly cosmetic items.
It will have Native Linux support at release.
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