Most "Doom clones" just showed static maps and lighting too. They aren't really games at this point, the are just demonstrating the techniques to create some aspect of the game, usually a world view like in this project. Within this project you see voxels with textures, rudimentary world building, and interaction with the world controlled by the direction the camera is looking. I think that is sufficient to call it a "Minecraft clone." This still has a ways to go before it can be called a game, but that wouldn't make it less interesting as a teaching aid.