Kiwi³ Engine is a game I'm working on. Let me explain. KiwiCubed Engine is supposed to be a highly moddable game. All vanilla content will come in the form of pre-installed content packs (except for some extremely base content so that you can run the game with zero mods). As well as those vanilla packs, you'll be able to install custom packs to mod the game. With this system, the game can act more like a game engine or just a highly moddable game. Kiwi³ is intended to be more of a "Minecraft engine" than a voxel engine, because it doesn't use traditional voxels or voxel rendering, but rather uses elements more similar to Minecraft.
Kiwi³ started from a place of distate for Minecraft I have. Minecaft has a lot of issues, too many too list. Kiwi³ in both the engine and vanilla content pack side is designed to not have a lot of these issues people have with Minecraft.
(This is in no way a comprehensive list, but rather a list of anything I could think of off the top of my head)