The battle system is similar to the battles from previous titles. The icons provided are Jump, Hammer, Bros. Items, Items, and Run. The Bros. can defend with their jump and their hammers. The Jump makes Mario and/or Luigi jump to dodge an attack or to counter-attack. The Hammer is used to counter-attack.
Each brother has his own HP, POW, DEF, SPEED, and STACHE points. When the brothers finish a battle, they each gain EXP points. With enough EXP Points, a brother can level-up and increase each respective statistic.
- HP (abbreviation of Heart Points) is the amount of life the heroes have. When an enemy hits one of the Marios, he will lose HP. When his HP reaches zero, he passes out, but can be revived with a 1-Up Mushroom or 1-Up Super.
- POW (abbreviation of Power) is how strong either Mario or Luigi is. The higher his POW stats are, the more damage he will give.
- DEF (abbreviation of Defense) is how much damage either Mario or Luigi can block from an enemy hit. The higher his DEF stats are, the less damage he will receive.
- SPEED is how fast Mario or Luigi are. The more SPEED he has, the sooner he can attack an enemy in a given turn.
- STACHE is the most unique of Mario and Luigi's stats. The higher their STACHE stats are, the greater there is a chance of a Lucky Hit, which doubles POW. Plus, it gives Mario and Luigi discounts when buying at shops.