icecreampie0, use your super arrow buff for the angel. He goes down quick. I did the same for the other big bosses like the black dragon, red dragon etc. With the super arrow buff and your giant army if you followed my guide you would win everything.
Ok, for all you people having trouble. I beat this game with Humans, all you do is basically research full Human Tower, Barracks. Ignore everything else. When the game starts just hit 0 for autoshoot on arrows. DO NOT BUILD ANY UNITS ARROW TOWER TAKES CARE OF EVERYTHING. Level up your tower while boosting your maximum mana. Repeat this till you have 9000-9999 mana. Then max out your barracks and start sending nonstop cannons/paladins alternating with them whenever they're off cooldown. Use your super arrow buffs for the giant armies the enemy sends out when their castle gets hit. Late game you should spam some wizards too if you have them. That's pretty much it, this is sure fire way to win.