Head Hunter Trophy in Iron Sea Defenders

This is a cumulative trophy, and will pop when you have earned 100,000 gold in Levels. I believe only gold awarded for enemy kills counts, not gold from base HP or farmed from mines.

Regardless, this will come very early on, at least on PS4.

On Vita there are reports of this not unlocking, and the work around seems to be to earn all 100,000 on a single Level. This may have been patched, but if you are playing the Vita version and do not get this by the end of the first Campaign, have a look at this thread for a work around.