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I want to keep it
even if it does it should stay installed on your computer until you uninstall it (or windows 10 deletes it for being disruptive to the os if you have /update to win 10
it will most likely get removed once the full game (or a new version of the demo) is released, but that won't happen anytime soon.
Not considering we're looking at a Dec 2017 earliest release...
If you want to keep it, then download the standalone installer.
Has it been recalled or something?
Well it's at Humblebundle if anyone wants it. I have no idea why it's not on GoG or Steam. Perhaps something associated with the Kickstarter.

Hope these guys can make a decent game. It is often harder to recapture the magic of days past, even if you bring back the original developers, who are at a different stage of their professional lives.