So many people missing the point of Notch's tweet.
It's not about if you can run Minecraft on Win8 outside the appstore or not. It's about the slippery slope MS now created with Win8, the potential of taking away control from the users. MS is following the Apple route and anyone who thinks Notch's a hypocrite then they should evaluate if they want PC gaming completely controlled by MS in a decade or so or if they still want the PC as an open platform.
The fact is simple, Win8 sets a dangerous precedent. Sure you can still run stuff outside the app store but the precedent, and consecutive slippery slope, is now established with Win8 and anyone who doesn't see this is either blind like hell or an idiot.