The enemy may seem tough, but the fight will be easy if Zack stays behind it and avoids frontal attacks, as the tank's weapons are all placed in the front. Hitting it with Costly Punch quickly before it releases another wave of Panzer Jr.+s will really help in the battle. If there are no Panzer Jr.+ in the battle, it will use Eject! to summon five more.
Panzer is a German word that means "armor," and is an abbreviation for "tank" in that language.