In addition to being a fine RPG, the original Mario & Luigi: Superstar Saga for Game Boy Advance was notable for its keen sense of humor and its brain-twisting puzzles involving the use of both Mario and Luigi in tandem. The sequel on Nintendo DS is raising the stakes by adding two additional characters, Baby Mario and Baby Luigi, who join their adult counterparts when the latter duo travels back in time.

With four face buttons, the Nintendo DS has no problem keeping up with all four brothers, but players are definitely going to have their hands full. As in the previous game, each character is assigned to a particular face button, so you can make each hero jump independently at any time, in the field or in battle. You can also split up the adult and baby duos to send them in different directions, and as with the last game, there may be some times when you'll control just one character. The L button switches between duos, and R activates special abilities to help you navigate the complex environments.

While in the field, the action usually takes place on the bottom screen. The top screen shows a map of the local area…a useful tool once the characters split up. Occasionally, one duo may find a pipe or spring that allows them to go underground or above the clouds, respectively. That means they could end up directly above or below the other duo, at which point each screen will show a duo. Puzzle shenanigans will ensue.

During battle, you may have control of two or four characters, depending on whether the duos were together when the encounter began. Each hero can jump for special attacks or to avoid enemy attacks, and all four plumbers (or plumbers-to-be) have hammers. So far, special attacks seem to be limited to the use of items, which initiate powerful, interactive moves that may involve as many as all four characters. For instance, the four-man trampoline sends all four brothers high into the air (as depicted on the top screen, which normally displays an empty sky). Then each character drops down onto the enemies, one at a time, and you have the opportunity to press that character's button at the right time for extra damage. The game may also include "Bros" attacks as in the previous adventure, but they haven't been shown yet.

Mario & Luigi 2 is certain to carry on the hilarious spirit of its predecessor. NOA's localization experts have mentioned to us that the psychotic Fawful, a favorite supporting cast member in the original game, has so far not been seen in the sequel. But they assured us that there are plenty of other crazy characters, including some great new ones. Mario, Luigi, and their youthful doppelgangers are typically mute, so the story and jokes have to be told through numerous non-playable characters.

As one of the first RPGs for Nintendo DS and a radically expanded sequel to one of the GBA's most beloved games, Mario & Luigi 2 is sure to be a big hit. You may want to start practicing your multi-tasking skills now.