Here is the full list of all 15 Constant C achievements worth 200 gamerscore. It takes around 6-8 hours to unlock all of the achievements on Xbox 360.
Complete story mode.
Gather all the storage devices.
While free-falling at a high speed, change the direction of gravity and apply brakes.
Find the dinosaur.
Discover the phone-microwave.
Chase Ellie 2.0 through all the levels where she appears.
Exceed 150 deaths.
Reach the storage device location in D3-3 and complete the level without dying.
Change the direction of gravity in the midair at least 10 times and land safely.
Collect any storage device inside the 6th door without using the second time field.
Complete C2-2 in 5 seconds.
Complete C3-3 in 5 seconds.
Complete C3-4 in 7 seconds.
Complete F1-5 in 20 seconds.
Complete D1-5 without falling off the ball unnecessarily.