Here is the full list of all 47 Splasher achievements.
It's all going splendidly
All in a good cause
Get Water
Complete the game in Standard mode
Rescue all the Splashers from a level in Standard mode
Rescue all 154 Splashers in Standard mode
Complete a level without dying
Go Splashteam
Get Water Stickink
Get Bouncink
You should have held that door!
I get knocked out, but I get up again!
A friend in need is a friend indeed
Give yourself to the Dark Side
You're never going to keep me down!
Fries anyone?
A good Potatrooper is a drowned Potatrooper!
Lasers are my calling card
Off to a flying start
A bird with two stones
Mashed Potatroopers
Why is it always me?
A good Potatrooper is a dead Potatrooper!
Complete all the quarantine areas
Jump and you're history
You rang milord?
A close shave
Complete a level without jumping
699
At least I'm not the only one
Right time, right place
Two Splashers in the same place? Impossible.
Get your first Medal in Time Attack
Get your first Gold Medal in Time Attack
Get your first Platinum Medal in Time Attack
Complete a Selfish Speedrun
Complete a Standard Speedrun
Complete a Gotta Catch'em All Speedrun
Get your first Medal in Speedrun
Get your first Gold Medal in Speedrun
Get your first Platinum Medal in Speedrun
Complete a Speedrun without dying a single time
Get all the Bronze Medals in the game
Get all the Silver Medals in the game
Get all the Gold Medals in the game
Get all the Platinum Medals in the game
Get all the Achievements. After that, you are definitely one of the best players on the planet, perhaps even the best ever! Continue to prove it in the leaderboards!