Zombie Challenge

Overview
There is a campaign that can to test out how far player's base defense will survive against the hordes of zombies. This campaign will unlocked/available at Spaceship level 3

Rules

 * 1) Take part in Zombie Challenge, Player can get plenty of survivors if their defense is able to withstand from zombies
 * 2) Your heroes will also defend zombie’s attack
 * 3) Difficulty level are divided into 4 levels, they are
 * 4) * Normal
 * 5) * Hard
 * 6) * Extreme
 * 7) * Hell
 * 8) Each difficulty have 20 stages that marked by alphabets & each stage have 3 waves
 * 9) Level of zombies will increase every stages, according the difficulty
 * 10) Player have 3 chances for free, player can add more chances by spending a sum of crystals
 * 11) If losing from these challenge, player won't lose their chance. If won, chances will decreased
 * 12) If player win some stages, player can use swipe button challenge to shorten the time, but their chance will decreased
 * 13) Chances will add in 8 hours per chances from player's challenge
 * 14) Player may capture zombies to fight for player. Captured zombies will stored in Zombie Camp

How to Play

 * 1) When on the base interface, press Campaign button for enter the Campaign interface menu
 * 2) At the Interface, press Zombie Challenge button menu, player can choose which challenge level will be
 * 3) Level of zombies will increase every stages and difficulty and the number of zombie hordes that will appear will be random, more difficult are many more zombies will invade your base
 * 4) Builder can help player base from zombies attack by repair damaged buildings (except hero). So, don't let builder station get downed
 * 5) If player base can survive in 3 waves of zombie attack, player will get plenty of survivors & captured zombies. Captured zombies will stored in Zombie Camp
 * 6) Every Monday and Tuesday, reward of survivors will be doubled