Defend your castle from the invading force (with a little help from gravity).
Pick the attackers up and toss them to score points. Once you have the Temple upgrade, drop attackers in your castle to convert them to the “right” side. Once you have the Archery Range, you can train your Converts to be archers by clicking on the red flag. Archers each require 200 points upkeep per level. After getting the Demolition Lab, click on a Convert to send him out on a suicide mission. Click the bomb-laden guy to set him off. The Workshop is where Builders are trained (green flag). They will rebuild your castle when it’s damaged, and require 50 points upkeep. The Manapool lets you train Wizards (yellow flag). Wizards also require 200 points upkeep, and can cast three different spells. Kill destroys a single attacker, Detonate makes him explode and take out attackers near him, and Conversion instantly converts an attacker. Keep in mind that if you don’t have enough points, your workers will leave.