I played more than I was expecting.
Small deck of healing, blocking, and thorns is over powered. But I picked that to deal with the hoards of enemies. To me other cards didn't seem worth it.
The reward cards can be all over the place. 0 energy 3 block is OP. Most high energy cards didn't seem worth the cost.
Took me forever to understand cleaning decks. Sometimes the remove options was open at the start so I thought I was replacing that card with the one I choose. Once you click on the remove button it only changes cards. Maybe have your deck size listed on the page so the player sees the deck size get smaller? or move the clean button so the user doesn't click it coming from a battle.
I only really put thought into what cards I removed and added into the deck. Other wise I was mindlessly using all the cards until I ran out of energy.
Interested in seeing future updates.