Here is the full list of all 10 Five Nights at Freddy's achievements worth 1,000 gamerscore.
Kept Freddy from getting to cams 4A or 4B during night 5.
Kept Foxy from escaping during night 4.
Experienced a jumpscare, and then... who knows?
Completed the custom night on hardest difficulty.
Survived the 6th night.
Survived the 5th night.
Survived the 4th night.
Survived the 3rd night.
Survived the 2nd night.
Survived the 1st night.