Super Paper Mario is, at essence, a (quasi-)2d platformer. It's simplistic, colourful, and even satirical.
Within this town, the player can interact with NPCs as well as get involved in side-quests and even a virtual video-arcade. These little distractions are a nice addition to the main game.
The main game is divided up into Chapters, and each Chapter is split into four levels. The gameplay is mainly platform hopping and enemy stomping, with a little problem solving thrown in for good measure. This is my main gripe with the game though - the gamplay styles are too watered-down.
It seems like they intended to cover the best areas from RPG games and platformers, but it never really came together that well for me. The platforming is hardly challenging, and the RPG elements are hardly interesting. The item and leveling systems are very basic indeed.
The inclusion of Peach and Bowser as playable characters excited me, but their actual role in the game is minimal and sometimes even forced.
Visually though, the game is very cheery and colourful. The sprites (and they are 2D sprites!) are comical and lively, and the dialog (if you don't mind reading in your video games)is fairly interesting and sometimes even out-loud laughable.
Long-term interest in this title may wane, as once the main mission is complete, their are only a few chores left to tidy up, and admittedly, some of them aren't so fun.
I have mixed feelings about this title. On one hand, it is a very original concept, with funny and kooky gameplay, but on the other, you kind of feel like the game was only a reflection of what it might of been, and the easy difficulty really does harm the replay value.