Here is the full list of all 21 Umichan Two Scoops achievements.
Beat the game without Maiko and Pattie participating in any adult situations
Complete Joey's ice cream.
Have a wardrobe malfunction
Complete Leyah's ice cream.
Get more than 24 Money.
View the Leo scene.
Complete Tsugo's ice cream.
View the Joiry scene.
Get cherries
Watch any replay.
Complete Savori and Amber's ice cream.
view Percival scene
Get strawberries
View Chris scene with Peach and Creamy
View Pattie throwing ice cream at David
View the David scene
Turn off the screen lock in the settings.
Make first ice cream successfully.
Watch the animation in the intro scene for 10 seconds or longer
View Maiko and Pattie's selfie images.
View the in game comic.