Here are some more Mario & Luigi 3 trailers showing the brothers working with Bowser to defeat the enemy.
Mario and Luigi work in Bowser's stomach on the bottom screen while Bowser goes on the rampage above. Bowser uses his strength and flame attacks to defeat enemies and knock down trees. We can also see the moment when Boswer drinks from a fountain, forcing the brothers to swim around in his gut below.
There's also an amusing battle scene where the brothers pop out of barrels.
