Cores and sub-cores

Crystal Cores

• Main Objectives are marked on the mini-map with a red trimmed yellow Shield Icon.
• Defending the Crystal Core(s) is the main objective in order to complete any map.
  If any Main Core gets destroyed the map will fail.
• The Amount of HP a Core has depends on difficulty and map.

Sub Objectives

• Sub Objectives can be identified by the spinning Grey shield above them.
• Sub Objectives are a secondary type of "core" to protect. If the Sub Objective gets destroyed the map won't fail but a new lane often opens on the next wave. If you lose the Sub Objective on the last wave it can be ignored.
• The Amount of HP a Sub Objective has depends on difficulty and map.
• Keeping Sub Objectives alive until the end of the map will yield bonus experience.