VANQUISH
50 Achievements
1,000
15-20h
Two Birds with One Stone
Destroy two or more enemy robots at once with the LFE gun.
20
How to unlock the Two Birds with One Stone achievement in VANQUISH - Definitive Guide
Jellyfish will die to the slightest scratch though so as soon as you see a couple of them go into slomo and shoot. Should easily kill 2 or more.
At the beginning of Act 1-6 (Darkness) and after the cutscene where the APC "Mike" bursts through, you'll see the LFE gun for the first time on your right side (yellowish). Pick it up, and immediately equip it. As you move forward, there will be a few bug like robots crawling your way. Just shoot at them with the LFE gun and the achievement will pop.
If you didn't get it right away, a little further on that same level, there will be some huge "jellyfish" enemies with a lot of green dots coming your way. Destroy one and they'll stop moving. The green dots will become red dots, and it then explodes. Be sure to equip the LFE gun before it explodes, because you'll get a new opportunity of smaller bug like robots to destroy with it.