Full list of all 28 Operation Darkness achievements worth 1,000 gamerscore. It takes around 40-50 hours to unlock all of the achievements on Xbox 360.
Completed Campaign Mission 01
Completed Campaign Mission 01 within 14 minutes
The conditions for obtaining this achievement are unknown
Complete Campaign Missions 26-27
Complete Eagle's Nest Missions 16-20
Complete Eagle's Nest Missions 11-15
Complete Eagle's Nest Missions 06-10
Complete Eagle's Nest Missions 01-05
Complete Campaign Missions 23-25
Complete Armed Recon Missions 13-15
Complete Campaign Missions 20-22
Complete Campaign Missions 17-19
Complete Armed Recon Missions 10-12
Complete Campaign Missions 14-16
Complete Armed Recon Missions 07-09
Complete Campaign Missions 11-13
Complete Campaign Missions 08-10
Complete Armed Recon Missions 04-06
Complete Campaign Missions 05-07
Completed Campaign Missions 02-04
Completed Armed Recon Missions 01-03