Successfully complete one of the following tasks to get a trophy:

  Novice Defender (Bronze): Clear wave 10 on any single map. 
  Seasoned Defender (Bronze): Clear wave 20 on any single map. 
  Expert Defender (Bronze): Clear all the waves on any single map. 
  W1 Defender (Bronze): Clear all the maps in W1. 
  W2 Defender (Bronze): Clear all the maps in W2. 
  W3 Defender (Bronze): Clear all the maps in W3. 
  Crystal Hoarder (Bronze): Clear a single map without losing any crystals. 
  Champion Defender (Bronze): Clear all 12 maps. 
  Veteran Strategist (Silver): Accumulate a total score of 50,000 points. 
  Overachiever (Silver): Clear a map with more than 10,000 points. 
  Four-Star Strategist (Silver): Accumulate a total score of 100,000 points. 
  Good Samaritan (Gold): Clear a map without deploying a Thief or losing a 
  single crystal.