This is really well done! And I particularly like the combat. Filling the field with your attacks and enemy attacks really forces you to decide if you want to risk getting more of your attacks or be forced to take a really big hit yourself. I love the strategy and risk-reward that you provide with this setup.
Can someone explain how the combat is supposed to work? I suppose that if I had more experience with these kinds of games it might be obvious.
The "attack" will be one of four choices: You attack, you attack with magic, the enemy attacks you, the enemy attacks you with magic.
So the optimal solution is: Maximize the attacks that benefit you while also picking attacks that either lessen the damage you take OR choose damage against you that set you up for bigger patterns on the next turns.
edit: looks like is can get deeper too. For example, bats have no mana and cannot attack with magic so it is a nice way to move some blocks without taking damage if you dont have any moves.