been playin this too,just beated the 2nd campaign...
it kinda plays like magical drop: the rpg with a few twist here and there,it's pretty good stuff but i wish the level cap wasn't so low altough i guess it's not really a problem since the game feed you a new character right as you are getting near the cap...
one thing that annoys me is how idle units absorb attack when they get destroyed,all the cpu has to do is calling for reinforcement and ta-da! it's like nothing ever happened,it's especialy annoying against undead since not only it means your attack didn't do any actual damage but you also gave them some nice extra wall to block stuff...
maybe there should have been a delay for core unit to be called again in case they were destroyed so that at least it doesn't feel like a good thing when your unit die
also i can't help but think that they made champion unit too powerfull,as soon as one of them swing the game is almost always over...