I played previous versions, so I'm really happy with the "unlock all" button.
I already won ascension 12 with the fighter & paladin.
Upgrading the smith card is very good, it probably should be a bit more expensive.
The "draw 2 cards" for 0 energy should probably at least also be tricky or exhaust. Haven't abused it, but it's doable to use (multiple) of those cards to just play your best attack 4 times in 1 turn.
I was surprised how good paladin was, the "1 extra turn" from fighter is seriously strong just for getting extra gold / farming more upgrades.
1 problem with the design currently I think is, "just upgrade your attack, maximise gold, upgrade smith & buy relics" is a good enough strategy. Which kind of undermines the deck builder part.
Really love this game by the way, I hope my criticism comes across as constructive.