Before getting to see the game's normal title screen jiggle with
saying Wahoo, press
L1 / R1 for Popka or
L2 / R2 for Lolo to appear in the intro alongside the main character!
The jiggle is still the same but the intro itself ends differently, interesting detail that's easy to miss...
Edit (02/22): as I wrote in the coments below Door to
Phantomile has a secret in the title screen, press L2 / R2 to blow some leaves!