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