PlayStation Move Heroes
49 Achievements
18-22h
PS3
Line Em Up
Destroy 3 Enemies With A Single Melee Attack
22.8%
How to unlock the Line Em Up achievement in PlayStation Move Heroes - Definitive Guide
SandeProElite, TheCaptain388
This is actually easier than in may sound. Start any melee challenge and get three enemies grouped together. Hold the 
button and swing your Move controller to right or left. This should kill all three.