I haven't exactly figured out how to get it but it may have to do with the responses/cipher we would have to decode when we meet EYES
GIVE ME KEVIN NOWWWWWWW!!!! HE IS AN OG BRO and RADFORD TOO
apparently one of the other ciphers is STARSABOVE for Eyes meet up
the two hidden achievements are mental illness (completing all the achievements) and Blessed Up (I think: this is when we get a blessing from Eyes)
blessed be is something we get from being blessed by eyes and mental illness is when you unlock all the achievements
sorry meant Mental Illness and Blessed be being the hidden achievement
Correction Mental Illness and Blessed Be are the hidden achievements