Here is the full list of all 24 Die O'Clock achievements.
First key in the clock
Sixth key in the clock
Last key in the clock
Enigma of lyre done
Enigma of puzzle done
Enigma of fuses done
Enigma of TV done
Enigma of map done
Enigma of closet done
Enigma of cuckoos done
Enigma of pentagram done
Enigma of ring room done
Enigma of lift done
Enigma of bowls done
Enigma of 5 done
Enigma of chess done
You died once
You needed help once
You played piano
You restart the game
Complete the game without dying
Complete the game without help
Complete the game
You beat the clock