Thanks for the feedback. Balancing late levels was tough because there are so many different strategies players might be using, and also some players will unlock more lab rooms than others.
Were you able to do the lab puzzles? They give access to some powerful cards. I will try to push an update soon that makes those puzzle less cryptic.
At least when playing Challenge difficulty, my intent was for the player to:
- Use some cards from the Laboratory (unlocked via puzzles). (Though I've confirmed that this isn't strictly necessary.)
- Change their deck to specifically counter weird fights such as 37, 53, 89, and 97.
- Skip some of the non-boss levels if desired. (You can come back later with more energy.)
Should I make any of these assumptions more clear in the game?