Here is the full list of all 44 Sonicomi achievements.
Get Ending 13.
Get Ending 03.
Get Ending 01.
Get Extra Ending 01.
Unlock all hairstyles.
Get Ending 02.
Get Ending 12.
Get Ending 06.
Get Ending 09.
Get Ending 04.
Get Ending 10.
Get Ending 07.
Complete 100 photo shoots.
Buy everything in the Ouka Shop.
Get Ending 11.
Go on a second date with Sonico.
Get Ending 05.
Beat the game on Easy difficulty.
Get a bad ending.
Complete 50 photo shoots.
Beat the game on Hard difficulty.
Get a combo score of 200.
Get Ending 08.
Beat the game on Normal difficulty.
Beat the bonus stage.
Photograph 100 sub-targets.
Complete 10 photo shoots.
Go on a first date with Sonico.
Photograph a sub-target.
Get an SS ranking on a photo shoot.
Get a combo score of 100.
Get Ending 14.
Get Ending 15
Get Extra Ending 02.
Get the True Ending.
Unlock all clothing items.
Unlock all accessories.
Unlock all backgrounds.
Complete all Client Requests.
Get all bad endings.
Get all good endings.
Reach maximum affection with Sonico.
Take no photos during the tutorial.
Unlock all outfit parts.