It is (was) marketing failure and an unnecessary legal risk if this gets bigger and comes up on Enterbrain's radar.
You meant trademark, not copyright. Otherwise, your point still stands.
As for names, maybe something cute like ClojRPG?
For example side effects are just vectors of `[:tx/foo param]`.
But I highly recommend changing the capitalization of Maker to maker to avoid being mixed up with the product RPG Maker. Adding "an" helps signal that it's a descriptor instead of a name too.
Core: An RPG maker and engine for Clojure.
CrystalCore - because RPGs must have some sort of magic crystal, it's the law
CreataCore - why limit the name to RPG theme in case it develops into something larger?
Just a few quick name suggestions for OP.
Proper grammar would be "an RPG making tool".
Additionally, you deliberately wrote "RPG Maker" rather than "RPG maker". Capitalization is important, kind of like how "US bank" and "US Bank" mean completely different things (former is a generic reference to an American bank, latter is the name of an American bank).
So yes, I would change the name if I were you (and you have from what I can tell, good job) because it's infringing upon the RPG Maker brand and trademark but most importantly because it's just confusing.
I think HN automatically converts post titles to title case. (There's a short window of time to manually edit the post title to fix the capitalization.)
I really don't think it's unreasonable to assume this had something to do with RPG Maker when it was written like that.
[1]: https://github.com/damn/core/commit/72682f512343c596bce84f0f...