Here is the full list of all 30 Hannah achievements worth 1,000 gamerscore.
Finish Chapter 1
Finish Chapter 2
Finish Chapter 3
Finish Chapter 4
Finish Chapter 5
Finish "Hannah"
Obtain ending A
Obtain ending B
Obtain ending C
Obtain ending D
Watch the first videotape
Obtain all videotapes
Obtain one floppy disk
Obtain all floppy disks
Make a larva explode
Fall into the void after missing the first rope jump.
Spend 7 minutes inside the TV Room
Throw a box into the void.
Find a helmet from a very imaginative kid.
Find a war memory.
Find a time capsule.
Get everything in "Let's Dance"
Get through Chapter 3 without being spotted once by the Bullies
Insert a famous code in the controller in "Puzzle Islands"
Get everything in "Puzzle Islands"
Climb "The Lighthouse" without falling once
Finish the game without getting electrocutated once
Finish the game without being swallowed by a Hand
Solve "The Nursery"'s puzzle in a secret way.
See both sides of "The Hospital".