Sell 10 towers in a single mission.
Finish the first mission.
Build all tower types of one race in one mission.
Survive 60 waves on the Survival game mode.
Complete all levels in Limited Resource mode.
Destroy the Minotaur Base.
Win a level without towers.
Use the unit info 10 times.
Finish the Campaign.
Use all Economy Upgrades in one mission.
Win 5 multiplayer match in a row.