Hi, BlackKid
Here's on itch.oi you can buy a current (last update) version - the new updates are released like separate titles and you need to buy it again (like next episode of movie or Netflix seasons).
We are indie developers and create our game by crowdfounding model.
If you wanna support the game and us(developers) than you should look to our Patreon or SubscribeStar sibscriptions(our patreons are get a new updates for subscription).