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