It's fun, but ironically the black cards make it feel like I'm losing to RNG rather than a skill issue sometimes. Also I don't understand the logic that determines what you gain at the end of each level. I know it's two cards, but whether you get a lv 5 Star or a lv 2 Scissors seems random to me (and is critical in determining if victory is possible or not).
It's also possible there's no RNG at all and everything is set on a single seed; I've only done two playthroughs so far ^^;