Could definitely use a hard mode.

you should upgrade this game with more cards and skills

Not very well balanced, some upgrades completely trivialize enemy encounters

Fun idea, still a little janky. By that I mean, like many people have already pointed out, Jasper + Ubredisum completely trivializes the game, and I think that adding a little extra spice to the chest option (I forgot what it's called, sorry) at the end of combat would be nice, like straight up giving you card upgrades and things of the sort, without taking away the library of course.