This level is complicated in structure, but easy to navigate. The easier way to go is up from the beginning. There are some enemies that will drop a pair of wings when they die. These things don't kill you, but they circle you and inhibit your firepower. To get rid of them, fly close to a lava pool so they hit the lava. Also, when you begin to run into clusters of clear bubbles, use any weapon but the Hunter to clear them out of your way. The mini-boss of this level is a fairly annoying one. He is hard to kill and you have to fight it while avoiding all the other regular enemies. Keep on shooting his head while avoiding the lasers he fires, and blast the missiles that it shoots before they get to you. When you get to a large open area full of bubbles, get as far forward as you can, and you should find a claw item near the rocks.
As you go upward, you will move into a room full of bubbles where the boss, Dust Eag, lurks at the bottom. Shoot the bubbles to get rid of them, and then concentrate on this thing's head. He will spew up a bunch of rocks and bubbles, and in normal difficulty mode or harder some small cannons will come with the junk, stick to the walls, and fire at you. Use the Snake or Freeway for this part. When he rises up out of the lava, he will begin to fire homing missiles at you. Occasionally he will stop and fire a spread of bullets or three huge fireballs from his mouth. Stay to the back of the screen, as he will slam down into the lava sometimes. When he stops and starts moving his jaws slowly or slamming his head into the ceiling, this is a good time to use the Thunder Sword if you have a claw, otherwise just keep shooting or you run the risk of getting hit by the homing missiles. Keep hitting his mouth until he goes down.