Hidden Achievements Here is the full list of all 4 Hidden achievements.Filter Achievement View View Image viewList view Sort by TrueSteamAchievement desc TrueSteamAchievement asc Achievement name desc Achievement name asc TSA Ratio desc TSA Ratio asc Gamers desc Gamers asc Steam order Date won desc Date won asc What are achievement flags? Click to find outApply Revealing the pastFound all diary entries in B3 floor Seeking the truthFound all diary entries in B1 floor Reaching the answerFound all diary entries in G floor Holding the evidencesFound all diary entries and completed the diaries