Instructions
Get to the platform on the left as soon as King Neptune tries to use his Rope of Fire on you; jump and change direction while running to avoid this attack. Leap over to the floorboard on the right side when on the platform.
Deflect the ice balls that the creatures behind Neptune spit at you by using the karate spin move. Send three ice balls flying back at each creature and you will defeat them. Alternatively, use one sonic wave on them to kill them instantly.
Jump away from Neptune's attack again and land on Mr. Krabs' platform. Leap across to the platform on the right and then to the next platform in the same direction. Jump onto the large platform.
Turn the five mirrors around to face the king and then return to Mr. Krabs' platform; just head back the same way that you came.
Hide behind Mr. Krabs. When Neptune shoots his laser at you, it will deflect first off Mr. Krabs, then off the mirrors that you turned and finally redirect towards Neptune's bucket. This will stun him.
Use your sonic wave to decrease the king's health meter now that his defenses are down.
Go back up to turn the mirrors again because they change direction every time they are hit. Repeat steps 1 to 7 until the King is defeated.
Alter your approach slightly when Neptune has two-thirds of his starting energy meter, because his attack will change. At two-thirds health, the king will use his electricity attack; jump on the board next to Mr. Krabs when you need to dodge this move.
Change your tactic again when a third of his health remains as Neptune will destroy the majority of the floor. Carefully jump between the reaming pieces of floor and make your way to the mirrors as usual.
Fire two sonic waves from behind Mr. Krabs when the king's health meter is almost empty to defeat him and complete the game.