Seriously needs a tutorial. Perhaps more than any other game in the last year. It could be a good game....but not as it is. The hearts seemingly can only be used pre-battle, the swapping of forces can only be done pre-battle, there's no explanation for how the hearts fuel the abilities, durations, effects of multiple hearts, does unlocking one monster of a type unlock all of that type -or just that one?
If not for the author comments below, even discovering that the hearts unlock abilities would have been impossible.
Needs a tutorial.