Enemies must be defeated in Tower Testing in order to progress.
Enemies come in a variety of elements, each with their own strengths and weaknesses. Each elemental enemy also comes in 6 archetypes.
Standard melee-range enemy.
Melee-range. Has a higher HP, but lower damage than normal enemies.
Attacks from range.
Attacks from range. Applies a 300% slow debuff to your tower when they attack.
Fast enemy that can leap towards the tower when close.
Bosses have a higher HP and attack than normal enemies, but only appear every 10 waves and give 10 (confirm) xp when killed.