The smileys and sounds depends on how many days are left.
You can choose to be notified about how much time is left.
To see the smileys/cats you have to add a widget to the home screen.
To add a widget follow these instructions:
1.Find an empty home screen space
2.Go to the apps screen and select the widgets tab
3.Find 'Happiest Day' widget
4.Tap it and hold
5.Place it on the home screen
You can install a live wallpaper to put a smiley anywhere on the screen and hear its sounds.
It can be installed either by long pressing on the home screen or from the app's configuration screen.
Tap on the smiley to hear it. Double tap on the smiley to configure it. Double tap on an empty place to move the smiley there.