Does the content of this game differ form the main game, or is it included in it?

I have never before in my life seen any game on any PC platform be controller exclusive. Either I'm living under a really large rock, or this is genuinely a first. I can't help but feel they'd be really easy to implement because I've done it myself so many times. I'm sure there's a reason, but man is it weird....

When I try to play the unity launcher loads up - the green bar fills then it goes to black for a second then back to desktop, game closed. Tried running in admin mode, same result.