Changes

All air enemies are [https://terraria.gamepedia.com/Demon_Eye Demon Eyes] (A unique type of enemies from the world of Teraria.) which are mini eyeballs that tracks and attack only the hero. They do not attack any type of tower or the crystal. Waves 1, 3, and 5 have infinite building timers, however Waves 2 and 4 start automatically after 30 seconds unless you ready-up before then.