Beat the First Level.
Unlock the Soldier Hero.
Unlock the Engineer Hero.
Survive a level with stealth monsters.
Unlock the Scientist Hero.
Survive a level with attacking monsters.
Survive a level with an attacking dragon.
Survive level 12.
Beat Level 1 On Hardmode.
Beat Level 12 On Hardmode.
In Endless Mode, Survive 100 additional waves.
Survive at least 30 waves without losing a life.
Rush at least half the waves on a map with 30 or more waves.
Complete a level with one life remaining.
Complete a wave without using a tower.
Build and Upgrade 3 different towers to the highest level possible.
Beat a level with at least 10 towers remaining.