There are 28 achievements worth a total of 1000 points
Complete Campaign Mission 01
Complete Campaign Missions 02-04
Complete Campaign Missions 05-07
Complete Campaign Missions 08-10
Complete Campaign Missions 11-13
Complete Campaign Missions 14-16
Complete Campaign Missions 17-19
Complete Campaign Missions 20-22
Complete Campaign Missions 23-25
Complete Campaign Missions 26-27
Complete Armed Recon Missions 01-03
Complete Armed Recon Missions 04-06
Complete Armed Recon Missions 07-09
Complete Armed Recon Missions 10-12
Complete Armed Recon Missions 13-15
Complete Eagle's Nest Missions 01-05
Complete Eagle's Nest Missions 06-10
Complete Eagle's Nest Missions 11-15
Complete Eagle's Nest Missions 16-20
Completed Campaign Mission 01 within 14 minutes.
Played on Xbox LIVE.
Completed a mission after obtaining the Muramasa Blade, Dragon Slayer, and Excalibu
Gathered all 12 pages of the Valhalla Report
Completed all 27 Campaign Missions.
Completed all 15 Armed Recon Missions.
Completed all 20 Eagle's Nest Missions.
Completed Campaign Mission 27 after completing all of the Armed Recon and Eagle's Nest Missions.
Completed Campaign Missions 01-27 within 35 hours.