This smells very similar to the issue with the tetris clone a number of years ago. The overall issue is that while games aren't copyrightable, the look and feel of a game can be copyrighted.
That ruling is really exasperating. The judge not accepting that the size of the tetris field is part of the rules of tetris is really weird to me. The tetronimoes don't even look similar in their comparison given the constraints of shapes made of four blocks, and, like, the texture obviously looks nothing like original tetris, it's just some basic-ass rendering of a shape with some color.
https://en.wikipedia.org/wiki/Tetris_Holding,_LLC_v._Xio_Int...