The description reads "Make the Razor Boars trample and kill 20 enemies." By replaying both the campaign and iron mode over 10 times, using not upgraded barracks behind mage and archer towers ahead of them to trigger the boars' charge, I've certainly seen more than 20 soldiers being killed by a charging boar. Questions:
Should the description read "...in one game"?
Or is this achievement bugged, or I misunderstand otherwise?
Any good suggestions how to do this? The only hints I found casually given here were not helpful.