Unbalanced and overrated
The strategy in this game consists of three basic steps: step 1) spam training to level up existing cards so that they're actually useful, step 2) go into the next battle absolutely clueless as to what the next opponent is (i.e. your battle preview is dodgy at best in adventure mode, nonexistent in unlimited), and step 3) exploit the hell out of the flaws inherent in the battlecard system.
Once you gain access to the Lightning spell, 90% of what follows is just a series of one-hit-KO battles... the other 10% involves attempting to stun-lock your enemy using attacks and defensive spells that don't make the stun counter wear off. Why you can drag out a 1-round stun for 3 or more rounds while you use your buffs AND make the enemy attack itself, I'll never know. Serious points off for that exploit even being considered.
And then there's the AI with its enhanced effects and sometimes reduced cooldowns, an even better exploiter than us if not OHKO'd or stun-locked. A few notables. The paladin, with two automatically stunning skills, can place a DOT effect, replenish its HP and power, and attack several times before the stun wears off. You get about 1 round of normal combat before you're drowned under stun again and die. The gunner was an interesting one to train on, since its heal ability was capable of far more than 25%--often coming close to a full heal so as to make it nigh immortal.
Good pictures (I hesitate to call it graphics since that's all the cards really are) and a CRAPPY system. Try again.