It' s not that bad but, aside from issues that every other turret defence game has, e. g. dumb turrets that don' t aim at the most needed enemy to aim to (the closest to the base), the 14th level seem pretty impossible, but maybe it' s just me, and the tornado draw summoning a lighting doesn' t help either. Perhaps the full upgraded mana should be 200 and it should regenerate 5-7 at the time instead of 2-3. Or you could mantain the game as it is and use my suggestion for an easy mode.