I liked this a lot. the upgrades felt nice and the unlocking of new cards was fun. my two big notes:

• the money-making aspect felt superficial and a bit confusing. I didn't realize I was getting money from the 'collection' as well as the cards in my hand until late into the game. the small amount of money made by the hand and difficulty of controlling when you are able to have high level cards in hand assuming you get rid of completed sets (as well as the weird curve they follow) made that whole cards-in-hand income thing feel pretty pointless. also, I never figured out if foil cards give you any more money.
• I desperately wanted for a way to bulk sell low level cards. I couldn't tell you how many of those upgrade points I would have spent on something like that. maybe this is because I neglected getting auto-merge until late, but I don't know how much that would have helped. I spent entirely too much time selecting and selling low level cards so they wouldn't get in the way of me drawing the high level ones I wanted to combine and complete sets. I beat the game and enjoyed my time, but if those issues are addressed and maybe some new content added, I could see myself dipping back in.