After the player gets close to the Death Egg, Dr. Robotnik jumps on the Ball Shooter and starts firing cannonballs from one of two hatches below the hill. The mobile of the Ball Shooter itself is set high enough to be out of range of a Spin Jump.
When the cannonball is fired from the lower hatch, it will roll to the left side of the screen. However, due to not gaining enough momentum on the hill to the left, it will roll back and crash into the closed hatch wall. The Ball Shooter's upper hatch can fire two ways, as it can fire cannonballs far off-screen where they break to pieces, or will not shoot far enough, causing the cannonballs to roll back into the lower hatch's wall in a similar way.
Cannonballs are the only things that can damage the player, short of touching the Ball Shooter without using the Spin Jump. When the Ball Shooter is ready to fire cannonballs, the hatch door normally raises up, where it acts as a platform while horizontal and will help the player reach the cockpit to hit the Ball Shooter. However, if the player has a Lightning Shield equipped during the battle, they can easily get to the cockpit by double jumping and continuously attacking. If the player manages to jump high enough when approaching the downward slope towards the Ball Shooter, it is possible to start attacking the Egg Mobile before Robotnik jumps onto the seat and defeat the boss before the battle begins.
Like many other regular bosses, eight hits are required to defeat the Ball Shooter. Upon the Ball Shooter's destruction, Robotnik falls down along with the destroyed machine. After that, the player will find an Egg Mobile that the playable character can use to progress to a platform below the Death Egg, where they will find the next boss.
The Ball Shooter's seat has small turrets, which Dr. Robotnik never uses during the fight.
There is a glitch where Tails can get stuck under the Ball Shooter if the player is using Sonic and Tails, which will make for an easy win as Tails jumps repeatedly trying to get out, but ends up damaging the Ball Shooter instead.
This is the only Act Two boss in Sonic the Hedgehog 3 that does not incorporate Robotnik's Egg Mobile.
This boss does not have an individual name in English sources; however, the three-tier boss structure of Sonic the Hedgehog 3 is known as Doctor Robotnik’s Final Challenge.