I'll leave some feedback on the current verison.
1. A merchant needs to be in the game to let you cut cards out of the deck. I don't want to be use the same "deal 1 damage" tiles you start with 4 copies of late in the game if the AI plays a deck full of effect tiles at that point in the game.
2. Someone should be doing damage when the board gets full with no winner. I had 1-3 matches already that dragged on too long where both the AI and me couldn't deal any damage to each other, and this went on for 70+ turns and 5+ minutes in the 2nd battle since we kept having full boards for many turns in a row.
This is too common in the first match too where you only have basic tiles and I kept tying with the AI for too many turns where I couldn't even end the match anymore because I don't want to take damage. This gets boring and a waste of time too quickly.
3. The AI could use improvement. I had one match where the AI could have beat me and ended my run, but it placed its O on a square that didn't win it the match and ended my run, letting me defeat it to move on to the next match. It should be more aggro in its plays to do as much damage as possible to the player, even if it leaves an opening for you to deal damage to it.
4. As a thought, the player should be fully healed after battles. You only can heal in reward screens, but they end up taking over a tile choice since you only get 2 at a time. Instead, it should be max health upgrades since I thought the "gain X% health tiles" were tiles to be added to my deck, only to find out that just heal me for that much health without adding anything to the tile.
5. Hearing that elites and bosses are in the game, make them pay artifacts with passive effects as loot that trigger when you do something like "when the board is full, if you have the most tiles, deal X damage to the opponent." They only pay tiles, and they aren't that rewarding right now to defeat.
6. Finally, add an option to view your cards left in the deck. On card draft screens, I can't tell what I have in the deck and I don't want to add something that doesn't sync with it if I don't ever know what I have to begin with.