Alien Breed
21 Achievements
PS3
WARMING UP
KILL 100 ALIENS
57.1%
How to unlock the WARMING UP achievement in Alien Breed - Definitive Guide
This is cumulative across all levels and weapons, simply kill 100 enemies total. Depending on how thorough you are in searching levels before completing your objectives you may have this as early as Alien Breed Level 3 - Power System.