I understand that it look longer than expected, but the lack of information for a long time, and the lack of research done related to the systems used and lack of manpower makes this very disappointing.
I hope that if the new game you are talking about goes on kickstarter, that you don't ask for extra money again to back a Linux version.
Updates on the progress would be great, at least screenshots or a technical overview of where you are, since it'd at least show it's being worked on.
The main issue it seems with this and many other kickstarters from around the same time was promising multi-platform support without doing the proper research and experimentation first, which would have helped avoid the middleware issues and over-promising.
I will say that the devs saying they'd refund the backing for Linux users is a great step. I've sent an email regarding that, so hopefully that'll be processed soon.