Here is the full list of all 30 Sayonara Umihara Kawase achievements.
Fail a Stage while holding a backpack.
Acquire a backpack.
Clear Sayonara UmiharaKawase +.
Unlock all Stages.
Clear all doors.
Use all characters.
Acquire 10 backpacks.
Acquire 30 backpacks.
Acquire 45 backpacks.
Clear Tadpole.
Clear Crab.
Clear Balloonfish.
Clear Tadpole 2.
Clear Crab 2.
Play Survival Challenge.
Clear Survival Challenge.
Clear all routes on Survival Challenge.
Browse the Illustration Gallery.
View everything in the Illustration Gallery.
Browse the Sound Gallery.
Play everything in the Sound Gallery.
Check all Walkthrough Tips in the Gallery.
Watch the Stage Tutorial of a Stage you've cleared.
Watch all Stage Tutorials.
Play your own Replay 10 times.
Catch a Tadpole.
Clear the second door in a Stage.
Acquire two backpacks at the same time.
Fail a Stage 20 times.
Fail a Stage 50 times.