Ribbit King/Extras

Collecting Bottle Caps
When playing Story Mode, you will amass Bottle Caps, which you can view in the Gallery (on Pickwick's menu). You can unlock these caps by beating your opponents or interacting with certain challenges. When you unlock a cap, a figurine (and short description) is added to the gallery.

Locked bottle caps have a silhouette of the figurine and a hint how to unlock it.

Unlocking Movie Clips
Ribbit King comes with 2 discs: the game disc and the "bonus" disc. Playing through the game will unlock short movie clips of the Ribbit King characters on the Bonus Disc. The menu where you choose which clip to play will tell you what you need to unlock each clip. It's generally stuff like: 10 Frog-In-Ones, winning 10 matches in a row, etc.