A Super Mario 64 modder has built their very own Minecraft-style voxel engine inside the classic N64 game's engine, and it turns out, it's even playable on a real Nintendo 64 console.
Arthurtilly is the creator of popular ROM hacks like the Mario 64 Randomizer and SM64: The Green Comet, and is also the co-creator of Mario Builder 64 tool (alongside rovertronic).
He recently posted a new video on his YouTube earlier this week, entitled "I made Minecraft run on the Nintendo 64", featuring an exciting 5-minute-and-a-half look at a new hack he's been developing, which, according to him, "uses multithreading to be able to seamlessly generate terrain and meshes over multiple frames without causing any lag."
As he goes on to explain in the video, the engine had to fit into 8MB of RAM, to run on the N64 hardware, but already comes with a bunch of features you'd expect from Minecraft built-in. For instance, it already supports "an infinite world", "multiple block types and shapes" including slabs, various biomes (lava, snow, deserts, oceans, mountains), and the beginning of support for fluids like water and lava. This is in addition to support for ambient occlusion and smoother lighting.
It seems he is also planning on developing it further in the future, listing a day/night cycle, flowing lava and water, the saving and loading of worlds, trees, and vegetation, and an inventory system among the new features he wants to implement.