I wish there was a way to force the game to cap at 500 balls or something. I have 700 scatter ball single hits slowing my computer in the boss battles.
For the last level I just took out all of the yellow, then moved all my troops to the teleporter, and finally launched an all out attack on black's base.
I went for the first gold attack and XP boost upgrade in the skill tree, then got the transmute and heal spell skipping everything else, I only got some of the potion path skills then I got the revealer spell and continued to fill out the attack path. Decimate and health/mana regen where my main enchantments for fighting through the levels but in the boss fights I got a duplicate set of armour that I enchanted with decimate and elemental defense. Over all this is a great game and I really recommend playing it, you progress fast, and I have always enjoyed the dungeon climb type games. :)
There should definitely be better loot after the boss fight and a stronger boss. After a day of over preparing I used little to none of my potions. The ninja gear is definitely a must have, even though I never actually got the chance to insta-kill the boss (and I doubt its even possible) having the 17% chance is very useful in exploring. The potion made by the person in the back of the inn was more useful as money then a healer, my health at the boss fight was at an 860 cap and I was not willing to let it drop to 60 with the huge damage dealt by the boss. You can easily obtain potions needed for the fight just in the 10 level climb.
Its kinda cheaty to give 20 levels worth of XP when I am offline at school. Every time im back on my raiders boost 10-20 levels. Other wise great game!