One big issue I've found with character progression is the huge increase in skill mana costs when getting a stronger version. Fireball is a great example where at rank 1 you deal 160% total damage for 6 mana, at rank 2 you deal 170% total damage for 9 mana. It is not worth the extra 3 mana at all, I have upgraded my fireball and don't even want to use the new rank. This is also on the warrior class where bladestorm originally costs 30% of mana and ends up costing 45% of mana. Abilities that use a percentage of your mana should never increase in cost. I suggest making abilities with an exact mana cost have the cost scale with the damage, i.e., 100% damage for 10 mana, then 110% damage for 11 mana so you always want to use the upgraded skill. Really awesome game, thanks.