→Worlds: Every world does not have 8 stages a mini boss and a boss.
The game is played out in 'stages' which act as the games levels. Each themed 'World' has 8 stages (excluding Showtime Island and Metal Mountains, which only have 3). There are some stages that play outside of worlds, such as the tutorial level Woodwin Village and the Bonus Stages(Pokémon themed stages).
Every Stage has the option of playing at a Normal speed and a Fast speed. Getting a Gold rank on both modes will unlock official game art on the lower touch-screen. In case of the Bonus Levels, you unlock character art and for World 8 you unlock Concept art.