Here is the full list of all 12 Lost Bits achievements.
Finished level without a death
Survived 2 levels in a row with 0 death
Survived 3 levels in a row with 0 death
Survived 5 levels in a row with 0 death
Died 1000 times
Collected 1000 bits
Beat half of the game
Beat the game
Finished the game with less than 1000 deaths
Finished the game with less than 500 deaths
Finished the game with less than 100 deaths
Collected 10000 points