Here is the full list of all 15 White Night Dream achievements.
Obtain the Contact Lens Case (Level 3). (Alley).
Unlock Ending 1. (Only meet the Detective (Alley) and the Mysterious Girl (Seaside))
Use this character to obtain 10 skills in Infinite Mode.
Obtain the Metal Plate (Level 3). (Red-light District)
Unlock Ending 2. (Only meet the Classmate (Red-light District) and the Suspicious Girl (Park))
Trigger this character's skill 30 times in a row in Infinite Mode.
Obtain the Black Card (Level 3). (Bridge)
Visit all locations in one playthrough.
Use this character for 8 hours in Infinite Mode.
Obtain the Cola Gummies (Level 3).
Story Mode Completed.
Obtain the Japanese Sparklers (Level 3).(Seaside)
Meet the strange lady at the Seaside for the second time.
Use this character to reach 1000 Drunk Points in Infinite Mode.