Here is the full list of all 17 Umihara Kawase Shun Steam Edition achievements.
Finish "UmiharaKawase Shun"
Catch all Squids during Squid battle
Catch all Kid Frogs during Tadpole battle
Catch 3 Flying Fish that jumps from the bucket
Catch Sharksucker thrown by Shark while in air
Finish "UmiharaKawase Shun" without losing a life
Visit all stages
Finish all doors
Obtain all backpacks
Catch all enemies
Finish Stage 0 within 15 seconds
Finish Stage 0 within 10 seconds
Use door that returns to Stage 0
Finish Pufferfish battle with only blowing it away twice
Let 3 birds land on body at the same time
Travel upwards 2 screens or more without touching the floor
Make a catch after moving more than 2 screens with lure attached to the enemy