Knockstone is completely free to whomever may wish to play it, and shall always remain so.
I spend the majority of my free time almost exclusively working on this game, but it takes a painstakingly long time and a lot of dedication to develop it. I also need to eat and sleep with a roof over my head.
Any contributions you make to the development of this game are greatly appreciated. It's your support that means development can continue and *prosper! Thank you.
(Please note that PayPal takes 3.4% of any donation amount, and also charges me 20p per donation.)