Double Dragon (Arcade): Mission 3: The Forest & Mountains

This level is the longest of the four in the game, but that's because it's technically a 2-in-1.
You first have to roam through a forest, fighting more punks, including more Abobos, that stand in your way.
Watch out for a broken bridge. Falling into the water at the gap is instant death, though this can also apply to enemies you can manage to toss in there.
----------
Then, you go far away from the forest to distant mountains. Fight more punks there, including more Abobos.
The ACTUAL boss of this mission was is even a Green Abobo. You should take advantage of the rocks nearby and keep throwing them at Green Abobo to clear him out quickly. Just mind where the rocks go, because they can go too far to the right that Billy won't be able to get to, even if they're still in plain sight.
Beat Green Abobo, and get ready enter the secret base to find and rescue Marian!