I can confidently assure you that this visual novel is not being abandoned at all. Adding new codes and shit to the software just takes time, and you need to consider how sometimes something goes wrong with the coding or whatever that you also need to adjust so the whole thing is actually playable for us in the first place.
Another thing is that sometimes Sam gets really into these updates and adds more than they had any idea they were going to at all.
Also Sam actually updates people about the progress pretty much weekly on Patreon.