Really good concept, main problem in my opinion was the enemies outscaled my cards too fast, maybe Tier 2/3 of the same cards with buffed up stats for the later stages with Knights and Barbarians?
Appreciate the feedback! As you've noticed the time constriction of the jam did impact the game design a little bit and we plan on improving it post-jam.
Very interesting idea and gameplay! The hero sometimes goes out of the camera's view and the swarm of bats tends to overwhelm him most of the time. Another thing I might recommend is adding a sprint button to little Timmy.
To expand it further, the nodes are divided into zones so when the ball passes by another area its targets are now new nodes. Works quite well most of the time :D