Yokozuna appears at the end of the Military Train (Stage 5) as the area's boss. He makes his dramatic appearance by suddenly coming from behind and managing to outrun and stop the train the player is traveling on with his bare hands. He starts the battle by firing guided missiles from the triple-cannon affixed to his back (these can be destroyed in midair).
He follows by unleashing two plasma shots that travel in tandem in a wave-like manner, one high and one low. Afterward, Yokozuna will pick up the locomotive and start slamming it; this is merely aesthetic, however, and does not inflict any damage.
His next attack consists in launching a series of bubble dimmers straight up, which then travel across the train's top as they drop.
After sustaining enough damage, the main second phase of the battle will begin, where Yokozuna climbs on top of the train to continue the encounter on a more personal level (as he lets off his grip on the locomotive, the train starts moving again).
He commences by once again firing guided missiles from his cannons and then follows by jumping back and forth on top of the train in an attempt to crush the player. His next move consists in advancing menacingly toward the left side of the screen, cornering the player and performing a kick. He then jumps back to the right side of the locomotive and starts banging it, unleashing fire waves that travel across its top.
After enough damage has been dealt, the giant robot will go haywire and fall of the train, which will then crash into it and bust it apart, ending the battle.
Yokozuna returns as the boss of Stage 2 in Shattered Soldier. It seems to have been upgraded from his last appearance, as now he has three forms.
At the beginning of the encounter, Yokozuna introduces himself by launching a rocket-propelled punch and blowing up the cart behind the locomotive the player is on; he then run toward its side.
The battle begins with Yokozuna repeatedly firing his rocket punch (which comes back to him) and charging on the train in an attempt to make the player fall off. The player has to shoot a cap on the side of his shoulder; if done correctly, he will flip to the other side of the train and repeat the process.
After sustaining enough damage, he runs forward and stops the train, picks it up, and launches three missiles straight up which then rain down on top of the train. Shoot his head enough to make him drop the train back and commence the second phase of the battle.
In his second form, he disposes of his large arms in favor of more aerodynamic ones, and then hovers onto the train. He kneels on the back of the train and his abdomen opens up, releasing fast-traveling saws that ricochet back off the train.
In the third phase, Yokozuna adopts a jet-like form and starts flying around. Shoot him enough and his jetpack will blow up, leaving him severely damaged and barely able to function. An overpass will then sever him in two, making the upper half to fall off and blow up. Shoot his still walking legs in order to end the battle and complete the stage.