i just got deep blue, and apparently im supposed to get an achievement for it... but i didnt... lol.. anyone else experience this

perhaps not

There is a glitch in the game that prevents you from getting achievements if you are not connected to xbox live. I'm not sure if you never get online in the first place how it would work but if you start online and then continue offline or get disconnected from live the achievements don't register. I disconnected right before i beet the last boss and had to go through the whole game again to get the achievement.