- SlashingArbiter
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- Exalted Legendary Member
Your linked gamertag only has the Campaign Complete: Normal achievement. You need to play through the "Prepare to Drop" cutscene-mission to get the completion shield on Bungie.net. Also, each mission must be played continuously (save and quit is not allowed, pausing is okay) on Legendary to get that achievement. In the mission select screen, check to see that you have the Legendary completion shield for each mission; if not, you'll have to re-do those ones.
The campaign completion achievements are stackable, so if you complete it on Legendary, it should unlock the Normal and Heroic achievements as well.
[Edited on 02.21.2011 3:05 PM PST]