Finished the game - completed it 100%. Grinding Dia is not really that hard if you find the right opponent, so it maybe took me an additional 30 minutes (about 2 hours to finish everything).
The game was just long enough for me to start getting an intuitive grasp of the mechanics, especially the cardinal and ordinal boards. I began making the right use of corners, sharp and flat cards, tactical placements in bad areas etc.
Mechanics wise after playing a lot, I am really curious how you could have programmed that AI. The game is simple and cards similar enough in power level that even underpowered decks can beat the champs over not too many attempts. Not sure if that is a good or bad thing. In a sense it detracts from a world where people follow players like sports stars. For them to lose to a deck full of lame monsters would make little sense. But for a short game, its somewhat merciful to never be stuck on one opponent for too long.
I think the game is totally decent as is and needs no expansion (perhaps a tiny bit more post-end-game content), but I am thinking about expanded boards with different mechanics, unique spaces, blocked off vertices and spaces, negative vertices, etc. If you wanted to, there is a lot to mine here.
This would also be a spectacular mini-game overlayed upon a more traditional RPG. In fact, I think it would be really cool to see more games with something like this as a mini-game.
Still in awe of your clean graphical design and total mastery of the the show picture move picture combo, not to mention whatever magic you used to program the actual card game.