Nice shrubbery!

However, the extra stipulations you've specified in the Copyright/Attribution Notice section are incompatible with the license you've chosen. You cannot specify extra restrictions that prevent the user from doing what the license allows. This includes selling the assets. 

That doesn't mean others should be able to make a profit off of your work directly, but such stipulations interfere with developers ability to distribute their game, even for free, when the game is distributed on a commercial site like itch, steam, android play store, etc.

Furthermore, under CC-BY-SA, people do need to credit you. It is not optional. It is pretty difficult for someone to sell your assets directly for this reason. Anyone trying to sell this asset would be required to credit you and link back here to this page. Any potential customers of that person would visit the link and see that they can simply get them for free. Why would they pay someone else for free assets? The point is, they are still permitted to try. This permits more free use of the assets and doesn't create weird legal complications for developers who want to use the assets legitimately.

Would you be willing to forego those extra stipulations? Until then, I must mark this as having a licensing issue in order to prevent your assets from being used in a way you may not want.

EDIT: Fixed, thanks! :)