ACHIEVEMENT - HOW TO UNLOCK A Bit of a Challenge - Complete all challenge chapters All on Offense - Completed story chapter 8 on normal difficulty or harder without building a repair station Arcadeologist - Reach wave 25 in Arcade mode Battle Hardened - Complete all story chapters on Hard difficulty Battle Hardened Hero - Get hero medals from all story chapters on Hard difficulty Bring Them! - Reach wave 3 in Arcade mode Elite Defender - Achieve a total score of 10 000 000 or more First Victory - Complete the first level. Gorg Buff - Check the credits Hard Measures - Complete all challenge chapters on Hard difficulty Little Extra - Finish a level on normal difficulty with 3 x the amount of money needed for the investor medal Looks & Brains - Meet Sereia. Master of the Universe - Reach wave 50 in Arcade mode Mind the Black Hole - Deploy the Black Hole for the first time. More Merciless than Ming - Complete all challenge chapters on Unstoppable difficulty Mothership Smasher - Defeat a mothership. No More Gorg - Complete the last level. One Satellite Man - Complete a level using only one satellite type. Radiant, Sir! - Meet the Radiant Beem. Skeet Shooting - Defeat 1000 aliens. Soon to be Hero - Achieve hero medals from 5 different story chapters Space Age Hero - Get all the performance medals in one level in a single try. Spare No Expense - Spend more than $15,000 in one level. Stardust - Shoot 10 asteroids The Researcher - Get 8 upgrade tokens. Too Easy! - Achieve hero medal in story chapter 3 on normal difficulty or harder without building a single Blast Cannon Unstoppable - Complete all story chapters on Unstoppable difficulty Unstoppable Hero - Get hero medals from all story chapters on Unstoppable difficulty Unstoppable Victory - Complete any level on unstoppable difficulty.