— Personally I would prefer an active control on the battle, because right now I'm not sure what's happening, I just know there are dices but that's it ^^
Having trees that resist to boulders would be a great idea ^^
Right now I think the easiest way to win is to upgrade weapons first, destroy every single tree with boulders a soon as you can so enemies can't hide, and then regen / upgrade health :-p