Here is the full list of all 31 Guilty Summer Kiss 2 - there are Bloody Secret achievements.
Put 100 likes to Hisano in underwear
Put 100 likes to Miya in underwear
Put 100 likes to Lisa in underwear
See the fight of Nakahara sisters
Show Lisa the photo of Arisu
Say "No" to Rei
Be killed by Rei
See Lisa betraing her mother
Kiss Lisa
Betray Arisu
Agree to help Hisano for money
Listen to Lisa singing
Die for Rei's sake
Find a new body for Hisano
Be seduced by the headmistress
Not to go with Miya to the lab
Prefer Lisa to Miya
Be called boring
Let Rei live in your house
Find Arisu
Become responsible for Miya's reclamation
Be saved by Miko
Talk to Miko all night long
Not to step on the shoelace when running away from Miya
Get into someone else's body
Tell Miya you love her
Prefer Miya to Lisa
Find out what heterochromy is
Hug Lisa
To mix up Lisa and Miya
Have a successful date with Lisa