Interesting read, but a growing trend in these apps is the overuse of animations, especially placing them in the sign up process and it gets in the way of the user's action. I want to sign up and use the app as fast as possible rather than wait for your slow animations and transitions to finish in order to show the "Next" button.

I don't mind about the easter eggs as long as they don't interfere in why I'm using the app, but overall it is 'well presented'.