Nodecore is a game that will appeal to fans of xkcd, hofstadter, turing machines, the game of life, dwarf fortress, and factorio. It has a small number of basic building blocks, with rich interactions between them. There are no mobs, no nightfall, nothing to rush you. Experiment and discover at your own pace. The game has many built-in challenges to get you started, and you'll soon be thinking of your own challenges as well!
To give you a taste of the rich interactions in Nodecore, here's an example. How do you imagine you would smelt something in a world with no furnaces? In Nodecore, smelting happens automatically when a block is next to fire. But you can't just place fire, you have to use fire spread mechanics. You'll brainstorm your own designs, figuring out where to place flammable and non-flammable blocks to get exactly the "furnace" you want, and you'll end up with a machine that truly belongs to you.