Kingdom Rush ReVengeance - Frozen Throne Iron (Impossible)

This challenge was quite tough. I tried using different combination and placement of artillery towers as well as different heroes, but nothing seemed to work. Then I decided to put a heavier emphasis on barracks, use Eiskalt to stall as much as possible and put the melting furnace in the middle further back. This finally let me kill the golems, which got close to the exit on the lower path. I also optimized my spell usage, which sealed the deal.