As far as your demo players go, you should do an evaluation as to how much negative or critical feedback you've received from them. If the answer up to this point is "very little" then that doesn't necessarily mean you're doing everything right, it just means that your players are being overly nice/don't care to provide deep feedback/don't really have enough experience to tell you where you are going wrong.

All but four players out of 30+ were known people. All who played stayed past midnight closing down the venue, for 8 hours total.

Completely random Craigslist listing people. Not friends.

It went very well.

This is a $17 game, as you said, it's not Mirrors Edge, which; as a matter of opinion I wouldn't consider a visually wonderful game but I'm not here to debate that.