Uhh tbh its over half, but its hard to say (?)
The author does release a patch every month, but there are still a lot of old scenes without drawings. Not to mention he could also add way more to differentiate old scenes from one another (some of the Krowley scenes are recolors nor unique among different characters.) He will probably not add any new characters to the village nor the elf village, but there is still the whole left side of the map that we cannot explore, and who knows what he has planned for that. There is plenty of content to play, but this game still at least around 3 years before it will be completed. There is no timeline nor progress bar/percentage so this is just a wild guess as there can be so much he can add if he wants to (animations or new scenes for old characters.)