Here is the full list of all 21 PopSlinger achievements.
Clear Purple Lounge!
Defeat Lylah Crashcourse!
Defeat "Carlos & Carly"!
Defeat Alpha Star!
Clear Purple Lounge Act II!
Defeat Akane!
Save the world!
Put Akane to Sleep!
Switch Outfits!
Get the B ending (or Above)!
Get the A ending (or Above)!
Get the S ending (or Above)!
Get the SS ending (or Above)!
Do a Single Progression!
Do a Double Progression!
Get your RANKMAN to "Popping"!
Achieve Dream Time!
Get a B Rank!
Get an A Rank!
Get an S Rank!
Get a Double S Rank!