Hello.
I'm new here, so i'm sorry if this have already been answered/solved. I looked through all five pages, and didn't find anything.
I have completed all 12 levels on normal difficulty, both campaign, heroic and iron. Yet, i'm missing the "Heroic Defender" and "Iron Defender" Achievements, which means i can't access the premium level.
I have looked through all 12 levels multiple times, and on every level it says i have completed all three modes on normal difficulty.
Hope someone has a solution.
EDIT: I can now access the premium level. I am still missing the two before mentioned Achievements though.