I had fun and played this one for quite a while.
The UI is strange in some ways. A lot of information could be rewritten---instead of describing Strength as (common attribute, no effect by itself), describe it as (Strength improves Strength-based cards). I wish you could view the enemy's cards one by one before getting into the fight, as it would help me prepare.
No bugs found, but when you sell small cards sometimes the damage value on the Sheep pet doesn't update immediately.
I found several typos, which was concerning. I couldn't catch them all, but a glaring one was "YOU LOOSE" when you get beaten by an enemy (should be "YOU LOSE"). Even the sentences that are correct are worded strangely. If you're going to release a demo on Steam, I strongly suggest finding a native English speaker who is willing to sit down and find all the typos.
One last thing; all three fights I lost were to enemies who had higher regen than me. Might be a balancing thing to look into.
If you continue leaning into the game's unique mechanics, I can see this being a quality game in the auto battler genre.