Here's the best army setup, you can use this for a faster and better gameplay.
1) 2 Legionaires (Crusader helm + Golden mask)
2) 1 Frost archer (Phoenix helm) + 1 Shadow archer (Dragon helm)
3) 1 Priest (Steel helm). Basic tactic is, kep distance from enemies with your achers, let legionaires lead the battles from the front, while the priest heals them. Make sure the distance is not TOO far, or else the archers' arrows will hit less often. +Tip: You can farm Multiplayer battles for all the hats specified above by clicking "Multiplayer", then sort by top rated and choose the battle you need for the hat you are seeking for. Hope I helped, love the game. :)
How to kill running white thingies with the many hands:
Run away, make them get stuck in a corner. Then get up, press Down/S and shoot them until they die. =)