Batt-icon Iron

The Iron Challenge is a challenge for skilled players.


Iron Complete
In order to unlock the Iron Challenge on a level, the player must have got all three Stars for the Campaign mode of that level. The player only has one life, and has to withstand a long, gruelling wave of enemies. Certain towers are locked in this challenge, most often it is two towers, but some stages are limited to only one. Like the Heroic Challenge, upgrade paths are limited to a certain level. Completion of the challenge is rewarded with a Star. When completed, the flag of the respective area on the campaign mode map will gain a silver tint.

Unlike other modes, the Iron Challenge does not indicate the number of enemies which will attack in the wave from each path - the enemy number is replaced with two question marks.


  • When playing an Iron Challenge on a level that featured a boss, you will often see a result of the boss having been defeated. For example, the Juggernaut's head is lying on the side of the road. This doesn't occur for all boss levels.

Related Achievements

Achievement Iron Defender IRON DEFENDER Complete all Iron stages in Normal difficulty.

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.