I sadly think that the game will not be release and that is has been dropped. I really enjoyed the demo and was looking forward to buying it :(
The developer explained the decision to drop it in this blog post from January 2020. They refunded their backers on Kickstarter back then as well. I just found the blog after waiting forever for updates here. It's pretty disappointing they never released that announcement on itch.
edit: The blog post doesn't say it's dropped , just that it's no longer in active development. So I suppose there is hope for it to one day be picked up again but it's been over a year without updates so I wouldn't hold your breath.