Challenge

Challenge mode is a Very Challenging Set of Modes
 * Endless Conquest (Unlocks at Level 15)
 * Grand Conquest (Unlocks at Level 20)
 * Stellar Voyage (Unlocks at Level 20)
 * Arena (Unlocks at 25)
 * Arcane Wheel (Unlocks at Level 25)
 * Nuclear Crisis (Unlocks at Level 35)
 * Darkness Hunt (Unlocks at Level 30)
 * Nebula Amethyst (Unlocks at Level 38)