Wow. Could be an interesting game. Could also be an interesting learning tool. It's a shame that it probably wouldn't be ported to Linux though.
I honestly think it's more interesting as:
- A demonstration of what's possible within Unity (it's extremely impressive, because Unity's built-in GUI system is pretty terrible and it's clear that there's some level of composability, etc. to the UI system being demonstrated)
- An experiment in creating a totally virtual, cross-platform (gorgeous) desktop environment within a single app that could be trivially run on any OS
But of course it's still a long way from the latter, if someone even wanted to take it that direction