This is usable in commercial games (modifying the assets)? It's CC BY? If I back you on Patreon 5$ month will all the assets released on that tier usable in commercial games without paying any more royalties than the patreon?
You cannot share the assets directly, but only projects you make using them. There is no credit necessary (as long as you don't take credit yourself or assign it to someone else, I don't mind being ignored LOL).
And that's right, there's no additional royalties. If you back on patreon you can use anything that you download from it under the same terms, commercial use for any project is fine, just don't share the assets on their own.