I quite like the idea itself, and the execution is fine for the most part. What I really dislike is that the randomness is way too much for my taste.
I do understand the rules about will attack when possible and combos. But this still leaves way too many rooms for questions. If there's two target that's attackable, which target will the piece goes for? If during the combo, there's two targets, which way will the combos goes? How does pieces with no targets behave? What are the odds that a piece will move in a turn? All these questions etc etc. All of these are very important when you need to formulae a strategy to play a turn properly, even if its random, at least the player needs to know how random it is.
I understand your implementations probably means that not all of it is random, just not explicitly stated, but like I said, the player need these information to formulae a good strat, so it seems weird to not list them out.
Beside that, I have some minor complains about the UI and the game probably need more juicing to help with the aesthetic, but these are just minor details compared to what I said.