Here is the full list of all 22 Sliiide Playtest achievements.
Clear all the levels in the Beach biome
Fail a puzzle but collect all the stars in it
Destroy 1 star
Solve 10 different puzzles without using the reset button
Unlock the Desert biome
Clear a level at both the day and night time
Solve 1 puzzle without using the reset button
Click on a Chumbo
Clear the credits level
Solve 25 different puzzles without using the reset button
Solve 50 different puzzles without using the reset button
Solve 100 different puzzles without using the reset button
Clear all the levels in the Desert biome
Clear all the levels in the Forest biome
Clear all the levels in the Snowy biome
Collect all the stars in the Desert biome
Collect all the stars in the Forest biome
Collect all the stars in the Snowy biome
Unlock the Forest biome
Unlock the Snowy biome
Clear all the levels and collect all the stars
Clear all the levels