Being non-commercial is not an automatic fair use exception. Being commercial does not preclude fair use. And rule concepts are not copyrightable, only the specific expression. Rules may have other IP protection, including patents.
That's not even true in the US anymore. You'd have to convert those rules into some sort of device, or argue that the game is a business method.
Being non-commercial is not an automatic fair use exception. Being commercial does not preclude fair use. And rule concepts are not copyrightable, only the specific expression. Rules may have other IP protection, including patents.