Oh, hey, it's Impy! I've played some of your games too, I really liked Summer Sweepers. Thanks for playing the game and I'm glad you enjoyed it.
I'm surprised and glad to hear that you played Summer Sweepers! Do you think that TF Card Battle may still get updated in the future? I would be very happy to see a small expansion that make endless mode more repeatable!
One suggestion that I forgot to mention is that the "take an extra turn" cards should get discarded on use. They're the main thing that allows infinite combos in endless.
The story mode is really great and I've had a very fun time unlocking everything, but it's nice to play with the multiple transformations for more than a single round and to see how far a character can be taken. Endless mode gives something new and aspirational to do after the main story is complete.