Steam doesn't offer refunds for their games - and many non-AAA titles on Steam don't have a Demo - just reams and reams of promotional material that makes every game look like the next Half-Life 2.
The Devs did mention they were planning on getting a Demo out, however they've prioritised getting the connection issues with their existing customers fixed first. I can only assume after the connection issues are working, and perhaps a bug fix/balance patch has been released, a demo will be made removing all of the inital problems. This would present a 100% working, balanced game to potential customers rathe than what I bought - not that I didn't love it 
