The free demo has been updated and its main link re-added to the main page. We took it down temporarily after launch because it was crusty and old and terrible, but we wanted to make sure anyone can try this out for free so we've ripped out all the old demo stuff and re-implemented the short single player campaign using our existing map framework. You'll have access to Faceless and Monster Girl, and can play as Krumble Jack once you beat him.
So if you're on the fence about making a purchase or unsure of compatibility, give the demo a try first!