Just watch the Scratch cat turn 3D. Then wait for it as it focuses into a larger Scratch Cat. Then it repeats. At the beginning when it asks what feature you want, 1 is normal, 2 is swirly, 3 is a line, and 4 is a big half-circle.
Fullscreen not recommended if you have a laggy computer/laptop. Otherwise it should be fine. New Feature: There are now 3 random sprites that it can turn into instead of just the normal Scratch Cat.