Fun! I like the core mechanics and the art direction is great. I like the characterization the characters get from the dialogue as well. That combined with the art gives them a lot of personality. I don't know how much of a story is planned for the full release, but I do find myself intrigued by the hints of worldbuilding or backstory, particularly for the player character.
Obviously it's not done yet since it's labelled a "mini-demo," but I'll give this feedback anyway, just in case anything hadn't occurred to you:
A "restart level," "quit level," or similar button is needed. Sometimes I realize just from looking at my cards and at the timers that it's impossible for me to win, and I'd rather just click restart or give up or whatever than play through 11 more moves just to be able to try again (especially if there's limited moves available - putting a lot of brainpower into losing doesn't feel great).
My second thought is that it would be nice to have a way to manually advance the dialogue. I do like the dialogue, but if I've just lost the same level for the fourth time, then waiting through the losing dialogue again gets old. (I also read pretty fast, so even in regular dialogue I found myself clicking to try and speed it up. I don't think it needs to be faster, because like I said I read pretty fast, and you definitely don't want the opposite of text going too fast for people to read. I think a manual advance is almost always preferable to a set timer - that way, the fast readers can read fast, the slow readers can read slow, the people who get distracted by something IRL don't miss out, and the people who care more about the gameplay than the theming can skip it).
Lastly, this isn't something I personally struggled with, but games as a whole are pretty hand-holdy nowadays, so giving just a little more in the tutorial for "going forward" might be helpful for people who are used to that level of direction. Not a lot more, just a "hover over cards/enemies/etc. to view their mechanics!" as the tutorial ends would probably do it. Introducing every new thing isn't needed, but telling people how to figure it out themselves might be good. (Tangentially related, I do really like the "hover to view mechanics" thing. This way, if you ever forget what something does, the info is readily available during the game, and you don't need to back out to an instruction manual or almanac page or anything like that.)