Sometimes they do, often they dont. And yeah I'm fairly sure I can hit someones head when they are standing still >.< But it's not just that, sometimes they eat almost a whole clip of an ak/m4 what ever before they drop. Pretty annoying. And well I just finished it. From about 19.00 to 2.30, didn't feel like I blasted through it but even with the million retries it's only like 1-1.5 hours longer than black ops campaign rofl.
The game wasn't bad but some things ruined it for me. Oh well, better luck with UC2.
Do not read if you still have to play Uncharted 1