Get 25 extra walls.
Keep 'em coming
Defeat at least seven bosses in one run.
Is This All You Got
Beat the game on difficulty "Overload 5".
Beat the game without taking core damage.
Get the same upgrade 25 times.
Unlock all rewards.
Beat the game without letting a mob escape.
Who Needs Abilities
Beat the game with seven towers.
Finish a wave with a fully shielded Core.
Beat the game without losing a tower.
Beat the game without healing towers or abilities.
Get a rare ability.