Here is the full list of all 21 Rubber Ducky and the Rainbow Gun achievements.
Type the 2nd section of the dialog from the 6th level backwards into the cheat code selector! Don't forget to puncuate and capitalize properly!
Convince/bother/bribe the dev until everyone gets this achievement.
Place fifty-jillion (100) plants in the bounce house at once.
Unlock all the levels!
. . . or it would have been, anyway!
I told you to go right, didn't I. . .?
Well, it's sorta' in the level. . .
Looks like someone just likes firing the Rainbow Gun. . .
Everyone knows it's the best part!
It's there, it's unique! Just look closely!
Buy all the costumes!
Well, it's still there. . . just less dire.
Have the game run below 30 Frames Per Second.
It's a practical paradise, just for you!
This one's not too hard to find. . .
Be addicted to social media.
You're the best! :D
Beat the dev's score on the last level! (You might want to shoot for around 1500)
Get below 8:00 in speed run mode.
Play with Death Epileptic Pixel mode on. (There's also a game of the same name)
You've defeated the derpy brother and unlocked a message from the developer. . .