After starting the game, Zilla Jr.'s friends from the Godzilla Series start talking. After all they are done talking, you take control of Zilla Jr.. Aim up and down and shoot, stomp the ground, do a claw attack, or do a tail attack. Zilla Jr. regains some health every second, and as the game progresses, Zilla Jr.'s life bar gets larger. On hard mode, your atomic breath is limited and you have to wait for it to recharge if you use it too much. Your main objective on the first level is to get through it without being defeated by the military and defeat the Crackler, who shoots energy blasts that can deal quite some damage. In level two, you go through the city again but this time you fight a giant helicopter. After the helicopter retreats, Zilla Jr. goes to an underwater part of the level where he is attacked by submarines and then goes to level three. Level three takes place on a forest, attacking you are the military and giant bees. The boss is also a giant queen bee. Level four takes place on a rocky prairie, and the boss is a giant tank. Level five takes place on the shoreline where the enemies are giant squids, and the boss is Crustaceous Rex, who shoots tar that can paralyze Zilla Jr. temporarily. The H.E.A.T. members learn that someone named Decameron Wintern is sending military weapons and "testing" them on Zilla Jr., and that he has built a mind-controlling device intended to take control of the monster. Level six takes place on sunset on the shorelines where you fight the helicopter again, and in a quiet night next to some mountains, where he fights the same giant tank. But the real boss of level six is Wintern's fortress, which basic military weapons and many missiles come out from. After destroying the fortress, the ending cut-scene appears, showing Zilla Jr. heading towards the sea with the H.E.A.T. Seeker on his side in the full moon.
Enter the password in order to unlock the following levels.