it credits the inspiration and there is no profit so i would say its prob fine. there are also already so many PK mods s oi think the dev is fine with it/doesnt care.
So i think the dev is fine with it/doesnt care.
I'm not sure how the dev feels about it now. However, I'd posit that the reason there are a bunch of PK mods is because the dev gave blanket permission (via the unlicense) for people to mod his game, even in closed source commercial games and even if they didn't provide him with attribution.