Here is the full list of all 38 Guilty Summer Kiss achievements.
Get 3 bad endings
Ruin the date with Sugawara Arisu
Ruin the date with Tanabe Rei
Ruin the date with Arai Miko
Get confessed by Tanabe Rei
Get confessed by Arai Miko
Get confessed by Sugawara Arisu
Get 3 good endings
Make a girl angry saying your very first line
Don't make a single date on the first day
Like the picture of Tanabe Rei in school uniform 100 times
Like the picture of Arai Miko in school uniform 100 times
Like the picture of Sugawara Arisu in school uniform 100 times
Like the picture of Tanabe Rei in swimming suit 300 times
Like the picture of Arai Miko in swimming suit 300 times
Like the picture of Sugawara Arisu in swimming suit 300 times
Like the picture of Tanabe Rei in underwear 500 times
Like the picture of Arai Miko in underwear 500 times
Like the picture of Sugawara Arisu in underwear 500 times
Arrange a date with Arisu
Have a successful date at the beach with Arisu
Have a successful date at your place with Arisu
Fail to arrange a date with Arisu
Fail a date at the beach with Arisu
Fail a date at your place with Arisu
Arrange a date with Rei
Have a successful date on the roof with Rei
Have a successful date at your place with Rei
Fail to arrange a date with Rei
Fail a date on the roof with Rei
Fail a date at your place with Rei
Arrange a date with Miko
Have a successful date in the garden with Miko
Have a successful date at your place with Miko
Fail to arrange a date with Miko
Fail a date in the garden with Miko
Fail a date at your place with Miko
Don't arrange any dates