is this game finished or still updating?
It's still updating.
I think every game on itch has a section called: more information -> Status: In development (in this case) If you see "released", then it is finished. the section it's above the download button.
Also, you can check Patreon. They've got the v0.19 Beta Build 4, 6 hours ago. That's a way to check if a project is still updating.