It was originally supposed to be a mod for Minecraft, but the devs decided to make it it's own game. Yes, it has features of some Minecraft mods (like Xaero's minimap), but that doesn't mean it's just a Minecraft clone. Plus, Minecraft itself was inspired by games similar to it, like Infiniminer. But, seeing how you instantly decided to make this kind of comment, I'm assuming you're too young to know it.