Just some random thoughts. Hope it helps. :
- I don't have the greatest computer, but I had low FPS despite a low graphics settings. There are possibly memory leaks as the game keeps getting slower.
- Enemy deck quality is too random. The first run I played I ran into a Champion on the ~4th room. It kept spamming that deals 6 damage ability from like turn 3 and I couldn't do anything. It is also common to fight against some cost-2 4|7 minions on the first floor while the floor-2 final boss being a complete pushover.
- Some obvious crafting balancing issues, for example:
- Exhaust active skill's cost is too low compared to Summon active skill cost. Minions can even activate Exhaust effects mid-fight, making the former has also everything the latter has to offer and much more
- Increase mana pool is too cheap. I once got a cost-0 spell that increases mana pool twice.
- Exhume spells easily creates infinite loop, but they can be dirt cheap in term of mana. Insane combined with increase mana.
- Discard and deal damage equal to cost is a bit too powerful: Craft a cost-20 card and bust your opponent.
- The Warrior feels particularly underpowered. Although the starting deck has some synergy, the benefits it offers is only on par with better cards at best, making the class inferior to the Adventurer, who may RnG good cards. For example, you can craft cost-1 3|3 cards , a highly desirable substitute for the starters. Extra health also only delays the inevitable if you are overwhelmed on the field.
- Inclarity. For example, it is quite confusing when you say "when you discard cards". Whether it means when I discard my cards, when I discard my opponents' cards, or when my opponent makes me discard my cards, or any combination of the above, or even if it is limited to discarding hands. Counter target minion spell is another enigma.