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