Zack will encounter three foes at once in this fight. The player should focus on defeating one of them at a time. Magic attacks will inflict quite a bit of damage on the machines, but standard sword attacks will work fine.
Zack should equip accessories that will nullify the Poison status to guard Zack against the Shot Machine's Poison Gas. Nevertheless, high Magic stats and Thunder Materia will be the best way to achieve quick victory.