Beat the game and got all achievements and yes it's hard, but the main problem is the lack of descriptions on the magic buffs and the fact that they can stack. I've used the katana wielders spammed and then gave the group stealth then double damage then bird and they've tore through ranks racking up lots of gold for more spawning early. Also magic bullet plus double damage to my biggest range class makes them do aoe damage much like the OP'ed grenaders on their other side. Took trial and error to figure out though, thus the less than perfect rating also the need to swarm/spam leads to lag issues.