The duck is there for a mystery scavenger hunt . No one checks the credits and when everybody starts to look for the duck they find it complete it and wonder why they went through all that trouble for an extra level.
Its not a duck. Its a Platypus and he is called Perry.
It is a secret level.
It opens a new level
First go to settings and then click on the credits.
Press the settings button on the bottom left corner then press credits then press the duck
Yes her hero was call 'Lova-Perry-Duck'! It sounds actually quite weird!
It's not on a level. On the home page click on the settings button, then click on "credits." the duck will be on the bottom
Click on the settings button at the bottom left corner and click the credits the duck is at the bottom of the screen
It takes you to a secret level.
Back of my car.
you get nothing just higher rankings in your scores
It unlocks a new level.