This achievement is driving me insane -.- I ABSOLUTELY refuse to lower the difficulty to easy to get these campaign achievements but trying to kill three of those freaking things on Legendary is so damn irritating. The hammer doesn't destroy them, it just keeps sending them flying ._.
I am doing it at the Defend point where they come through the corridor but a bunch of those things shooting like crazy all at once at you = dead chief in under 4 seconds. Been at it for 3 hours, I take my time, I keep trying different approaches but nothing works and I really don't want to have to lower the difficulty just to get this achievement. Why does 343i hate me Q_Q