Here is the full list of all 13 Sakura Gamer 2 achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Kurumi wants to help you out
Kurumi showed you her admiration
A stern face but not a stern mind
Enjoy a nice dessert with Suki
Enjoy a nice summer vacation
Convince Suki to stay
Tell Kurumi what's on your mind
Watch the cliché happen
Prove that the girls are 'madly in love'
Take a relaxing bath with Clover
Don't look up things in the internet
Suki prepared your favorite breakfast
Let Clover help you to relax