Needing only this map on Hard to finish all beginning maps on Hard in the Iron Challenge, I find it to be IMPOSSIBLE.
I've played it at least 100 times with every possible combination of Towers, and roughly the same number of units end the game. Heroes make no notable difference, with some of the units attacking seemingly immune to ANY damage!
Even being a Premium Player I find it to be a joke.
The lack of using Artillery, and Barrage Activated Spawns make it a Joke.
I'm pretty much over it, since it's always the same result.
Hope this tips will be useful for you - http://www.gamespedition.com/pc-games/strategy-games/tower-defense-games/kingdom-rush-frontiers/kingdom-rush-frontiers-tips-tricks-strategy-guide#
