Kilroy Gold Achievement
Find 25 or more Kilroys
Kilroy's are drawings on walls left behind by other soldiers. To make the achievement easier put in this code 4V35JZHQD6.
The code will just tell you when you are near a Kilroy. It will say at the bottom of your screen "You are near a Kilroy."
Follow this guide for the exact locations of the Kilroy's.