well i checked avatar awards today and noticed there is one for completing legendary mission without dying i did not have it unlocked but the first mission of Halo Reach is so easy that i didn't die on legendary but did not unlock the award why is this? its happend a few times that an achievment has not been given to me when i earned it such as the "survive a fall by killing an elite" achievment...i finally got it but there were a few times i performed the assasssination but did not recieve any achievment is there a reason for this?