Mario and Luigi Bowser's Inside Story is the second DS Mario RPG game. It improves on every aspect of the previous game giving an engaging story, fun gameplay, unique graphics and good sound.
The story is based on Fawful trying to take over the world making Bowser intake all the people in the Mushroom Kingdom. This leads to Mario and Luigi battling inside Bowser which inevitably forces them to team up with Bowser to save Mushroom Kingdom. The story is the best in the series and is very engaging.
The gameplay is strong. With Mario and Luigi gameplay being the same as previous games, the unique element is Bowser and while he plays much like the Mario/Luigi it keeps the battles new and engaging especially when he becomes huge and the battle require the use of the touch screen and to hold the DS vertically. My one negative is the need to find attack pieces to get special moves. I felt it was tiresome to run around getting these pieces, it would have been better just giving new ones once the characters reached a certain level.
The graphics and sound are good not pushing much of the DS graphic power but all the art looks good. Sound is what you expect in every Nintendo DS game.
Overall Bowser's Inside story is the strongest title of the series and truly defines a Mario RPG. If you have a DS, this is a must play game.