Here is the full list of all 15 Memoir En Code: Reissue achievements.
Key: Lei Disse
Key: Otoloop
Nine keys, one message
Key: Pieces
Key: Øresund
Key: Oranje
Key: Laurana
Key: S.S.S.
Key: Precisione
Key: Silippo
Read through all the dev commentary parts
Play until the end without skipping a single track (exc. Otoloop)
Find 44.4% of the decoding keys
Find every decoding key
A message for you