Hey Fullen! I played a lot of your game in my free time.
I successfully finished 14 runs, and I am pretty sure 10 of those were in a row.
I encountered some bugs: chains that involve things happening when cards get discarded and player gains health seem to get stuck i.e. everything gets animated, but the chain doesn't resolve, and the game makes a clicking sound at a constant loop (I think it's the health gaining sound). I got some screenshots when that happens:
Here's another bug situation:
Enemy cast a spell to gain life, and during my priority I cast my spell which gives me life, and sends minion on top of the deck. After the minion was removed, the game got stuck just like in the bug above. here's screenshot:
Let's talk a bit about balance, because there is none and that's not necessary a bad thing, but it might give you some ideas.
I tried multiple builds and strategies, and I am sure I found the most broken ones.
Example number 1:
Cards like that make the enemy not play any more, because every time they get a new card, they must get rid of it before they have the opportunity to use it. It's a pretty safe way to play.
Example 2:
It's nice to win when the enemy cannot do anything, but what is more even broken is winning before they even get to play! At some point after many successful runs the enemies got pretty strong. Their cards get better, their decks grow in size, and they get much more health. Not a problem. Let me introduce you cards, ad strategy that wins every time before my enemy plays a single card:
I think the last boss had 35 cards in his deck. I calculated I could remove over 80 before his first turn, so it really doesn't matter how big and strong he is, there are even more strategies to make it even more abusive, but there was no need. I basically just remove his cards whenever I play cards, and I can just play 0 cost cards, and stack the same effects on multiple cards.
The only way I though of how it could be countered is if in my enemies starting hand was a card costing 0-1 mana which could take control of my minion. I could counter that by having those kind of cards myself, but that edge case never happened, so I did not need to play it that safe.
Fixing it?
I don't think you should be completely rebalancing the game around bullshit strategies, because coming up with them is what makes it interesting. At this point I feel like I won the whole game, because I found that one strategy that always wins, but I got ideas how you could prolong the fun:
You should reward players for trying out different things instead of having them play over and over what works. You could do that with some sort of achievement system that would force players to come up with different strategies. To make that work, you would need to have the player be able to adjust the difficulty instead of keep increasing it until only the broken builds work. Have an achievement for getting 30 max mana, or 50 health, winning in x number off turns, getting a minion with x resistance and so on.
With that said, if you do want to balance the game, then I got some ideas.
Misc Feedback
At some point it became a chore to open card packs, especially when you must search for specific new cards whenever you want to add them to your deck. I think it would be nice to have an option of instantly choosing which cards you want to add to your deck from the "card opening pack" screen.
Other Bugs
At some point I tried adding mods. Making a new one did not work for me (probably to do with wine and linux), but adding images to the existing anime mod seemed to work. The only problem I noticed was how some pictures appeared zoomed in in shop:
Another minor bug is how the text saying "upgrades available" shows up even when everything is maxed out (I had over 1k of each resource, but no screenshots).
Help
At some point I changed my resolution, and went from fullscreen to windowed mode, and that completely broke the game for me (Wine on Linux). I tried searching for where the save with start up resolution and window mode is located to manually edit it, but had no luck. The only saves I found were in AppData/LocalLow/Fullen Games/Card Artisan
Is there somewhere else where you keep your saves? Deleting that folder did not seem to make any difference, which means the game is probably going to be broken for me the next DD if I don't manage to reset it back to how it was.