Really hated how the decks worked for most of the game. Felt literally unplayable with how much enemies put on debuffs to ruin your card draw, ruin your ability to get something going via removing your cards, enemies randomly having high damage cards that can OHKO you if you only have 20-30 cards, and the card deck also being your health making it difficult to manage both at the same time. The combat really didn't click for me, AI card art pulled me out of the vibes, and so I was very close to just dropping the game as soon as level two revealed the enemies getting a substantial health and difficulty spike.
Until I found the card that eventually ramps up to Chant: Heaven. A 30 damage nuke that requires effectively 9 mana to cast.
Suddenly, the 4 card limit was no longer an issue, as all I had to do is ramp up to activating Chant: Heaven and only doing minimal damage beforehand to make sure they hit the 30 HP range. Not much later, I unlocked several cards that allowed me to deck fix from any situation, with my worst scenario being stuck with 2 cards in deck and 3 + a status in hand, including a card that searches any Exorcism card which, wouldn't you know it, Chant: Heaven is.
The game immediately became me hyper optimizing the strat of finding the chants, getting the mana, and casting each stage before searching for my nuke. By the end of the game, the final boss had died within 2 turns, which would've been 1 if the boss didn't have a painful 92 HP.
Unfortunately, the game is literally only three dungeons set within a school, so I never got to see how far that deck would take me if the game continued further from there.