Easily see the secret words
In order to see see the words that you normally get by beating each
level, select "Blue" (that blue dog, from the show...) in the main
screen and scroll all to the right. After you reach the last
option, press right once more, and you'll see a new option, called
"A - Z".

By pressing it, you'll be able to see all the words that you get by
beating each level, apart from this game's credits.