guides
Do you ever get frustrated when playing the Xbox and you JUST CAN'T no matter how hard you try get the secret achievement? well this page is all about those frustrating ones. 
           MW3
This is actually a very simple achievement,
yet gives you a sustainable amount of G's.
all you have to do is on the level Turbulence,​
once you get to zero gravity, there will be 5 enemies. You have to kill them all before you touch the ground on any difficulty. 
OK guys, now this is actually a pretty specific achievement: so it's on the level ashes to ashes. The first thing you want to do is NEVER TOUCH ANY OF THE ASH PEOPLE. It's okay if the CPU does though. After you find Ashman, have many moments of sudden unexpected death, etc.,
you will go to Griffin's lair/hideout. If you look around, there will be a door with bars on it. Wait for Marcus and Griffin's troop to talk, he will open the door for you. If you keep walking through the door, you will see a jail cell with somebody in it. You'll want to interact with her. After that, she'll open the door and there you go.​