Is the Dusk game free?

Excuse me, I was wondering if you could clarify something for me. I came across a mention of the Dusk game and I'm quite intrigued. However, I'm not sure if it's available for free or if there's a cost associated with it. Could you please shed some light on this matter? Is the Dusk game indeed free to play, or does it require a purchase? I'd appreciate any information you can provide.