CorsixTH requires Theme Hospital assets but we didn't clone or otherwise steal anything that we ship, we require you to supply the assets precisely because we aren't. I presume that's true of OpenTTD as well. In the United States copyright protection for games covers the art and text but not the rules and Oracle vs. Google established reimplentations being fair even when exposing the same api. Truely novel game rules can be protected by patents per Nintendo.
Super Tux Kart does have battle mode somewhat similar to the Mario Kart balloon fight though not as polished (and many of the arenas are a little too large in my opinion). It also has a unique soccer mode.
I never understood why glibc needs to break ABI. It should not be allowed to. Ever.
You are not reinventing the wheel. Just maintain the damn thing and keep it running as is. As Linus once said "If there's a bug that people rely on, it's not a bug, it's a feature.".
Most of human history we didn't have electronic distraction devices and we have one Michelangelo; the answer is probably not as many as the question implies.
I agree that support is crucial, but stand by the "danger" of distraction. Digital distraction is a drug, and like other drugs has pros and cons -- I don't mean to demonize it. But it cannot be ignored.
We've collectively arrived at point where we could have a post-scarcity society where the arts could be a driving force for so many of us. It's painful to see these possibilities and know that they are out of reach because of the sociopaths who have power over us.
I have a question. Does the directed / no cycles aspect mean that webhooks / callbacks are forbidden.
I work a lot in the messaging space (SMS,Email); typically the client wants to send a message and wants to know when it reached its destination (milliseconds to days later). Unless the client is forbidden from also being the report server which feels like an arbitrary restriction I'm not sure how to apply this.