Center-sensei's Center Exam Episode 6

Center hosts an exam in which the girls must go into the world of the Border Break robot shooter game, where they can win a large number of medals. Saturn, the only one who has to go on foot, is made into a decoy for the enemy, while Dreamcast struggles with her controls, leaving Mega Drive to take on most of the enemies. Just as the girls reach the enemy core, the game world is hacked by Doctor Eggman, who shrinks the girls and starts causing havoc in the world until Sonic the Hedgehog appears.