Alien Breed: Impact
27 Achievements
12-15h
PS3
Killing Spree
Within 30 seconds kill 20 aliens in single player. Details for this achievement will be revealed once unlocked
51.2%
How to unlock the Killing Spree achievement in Alien Breed: Impact - Definitive Guide
Not as hard as it might sound. You will probably get this without trying. I got it on the second level of single player when escorting the physician. Alot of the smaller aliens spawned into the area at once and they go down pretty quickly. Anywhere that enough of them spawn is a good place to get this, though.