9 0 0Actions Report Solution Just play the ninth mission, Keyes, solo or coop on any difficulty and it will unlock. This is story related, you cannot miss it.You can also unlock these achievements in the mission if you follow the criteria:The Tying Up Loose Ends achievement in Halo: Combat Evolved Anniversary worth 25 pointsKill every Elite on the level “Keyes” on Heroic difficulty or above.The Popcorn.gif achievement in Halo: Combat Evolved Anniversary worth 48 pointsKill 100 Flood Infection Forms on the level “Keyes” on Heroic difficulty or above.Leave a comment