There are a maximum of 33 Half-Life 2 achievements worth 537
4,419 tracked gamers have this game, 674 have completed it (15.25%)
Pin a soldier to the billboard in chapter Highway 17.
Unlocked by 1,417 tracked gamers (32% - TSA Ratio = 1.76)
Do you have a question about this achievement? Please post it in the Half-Life 2 Forum