Just got to lvl 50, this has been teh easier "imposible" badge i have done. the game is cool but its too easy. Dont read more if you dont want to know how i did it: just took four rangers and got them as much dexterity as i could, forget about leather armor, just take items that have kill %, stun %, quickness (at least have 65 in each character), weapon damage, mana regeneration. Armor its just pointless.
This game sucks,
Only really interesting thing is "investigating" how units works but after 10/15 matches youll notice 2 things:
1st: almost everybody uses same kind of army or small changes of the same one
2nd: when you raise in score people leave battle when they see they cannot win you.
 "Monsters' Den"){kind=icon}
 "Tactics 100 Live"){kind=icon}
 "Desktop Tower Defense"){kind=icon}