Here is the full list of all 21 Umichan Two Scoops achievements.
Get cherries
Complete Savori and Amber's ice cream.
View Chris scene with Peach and Creamy
View Pattie throwing ice cream at David
Have a wardrobe malfunction
View the David scene
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.
Watch any replay.
Turn off the screen lock in the settings.
view Percival scene
View the Leo scene.
View the Joiry scene.
Get strawberries
Complete Leyah'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