I think these type of experiments are good for personal projects, but to clone someone else's work and charge for an unfinished ripoff seems like a scummy thing to do, especially when notch is such a valuable member of the dev community and a great model of indie dev success. Not only that, but the game markets itself as a clone and even steals part of the Minecraft name. When has that ever been acceptable in a for-profit context? I'd find this a lot less annoying if it were free and open source, as long as it didn't have reverse-engineered Minecraft source code.