I just noticed that in every stage of Kingdom Rush. I always use Meteor Spell or Rain of Fire to lessen the concentration of enemies then I thought of not using it.
i tried it on Stage 12 Iron Mode and I failed on the first try and didn't try again for I am going somewhere. I will try it again later.
Try it my fellow Kingdom Rush players. Have fun! xD I hope this make a kind of challenge to you guys.