I think the rings are a fantastic innovation. It would help me even further if the z-layers were colour coded too.
I appreciate the colours currently reflect different blocks like in the original tetris, but I'd find it easier to process the "board state" if each ring size also had a colour associated with it. It would be easier to "scan" the board state for where best to place the piece.
That said, this is a fantastic demonstration of innovation. It very neatly demonstrates the pros and cons of this particular 2d visualisation scheme.
The game itself is awkward, and requires 3 hands to properly play. Also for anyone else who grew up playing a particular windows port of tetris (from the BOWEP pack?), having space jam down the page instead of the block takes some getting used to.