King Kong 2: Ikari no Megaton Punch/World 7

Compared to the previous world, World 7 is far less complex, and the enemies present far less of a threat to King Kong's life. The biggest danger present throughout most of the stage is the cliff edges which can kill Kong instantly if he slips off one and falls. Jumps must be performed with extreme caution, and lateral movements are usually necessary to survive the landing. The far north portion of the world contains nothing but shortcuts back to the lower sections.

From the start at the bottom, be sure to travel left via the narrow strip of land at the bottom of the screen, and collect the Artificial Heart in the next room. You can also visit the room to the right if you rock power isn't at it's maximum level. From the bottom, travel up the center until you find the room which contains the Rock Case (one of the first primarily grassed over screens.) After you've collected it, return one room south, and go one room east to find the boss' hideout and challenge it for the key.

Boss
The boss of this world is a dragon. The only weak point on the dragon's long serpentine body is it's head. As the dragon accumulates damage, sections of the dragon's body will drop away and the dragon will become shorter and shorter. Eventually, only the head will remain, but the head can withstand a substantial amount of damage beyond the last body segment before it is ultimately defeated. Strike rapidly and repeatedly until the key is released.

After the dragon is defeated, navigate over to the west side of the world, and travel one screen south. Here you will find the warp zone that leads to the 8th world, and it will deposit you, not at the start, but in the lower left corner of the world where the Konami logo can be found.