Charge!

You'll start off in a shaft. Your first goal is to head left. You'll encounter some enemies here, so take them out. They're good for topping off your health and missiles, which is always handy. After that, climb your way up to the save room you'll see nearby and make sure to save your progress.

Now, head back to the shaft you just climbed and start ascending again. Keep going up until you spot a red door on your left. You'll need to use a missile to open it, so equip those and blast it open. Head through the door into the next area.

In this new room, you'll see flies dropping from the ceiling. Shoot them down as they appear. Be careful though, there are also acid pits on the floor. You'll need to do some careful jumping to get across them. Keep moving right until you reach another door. Go through it.

This next room is pretty small. You can shoot down any flies here if you want, but it's not essential. Just head right to the next room.

Okay, this part requires a bit of platforming. Jump onto the small bump in the floor ahead of you, then immediately jump right to reach a higher platform. Now, look to your left – you should see a small bump in the wall. Jump to that bump, and then jump left, passing *through* the wall. Yes, you can go through this section! Inside this hidden alcove, you'll find a Missile Tank. To get it, you'll need to shoot the fly nest. A couple of missiles or a good barrage of basic shots will take it out.

Once you've snagged that Missile Tank, return to the nearest platform. You'll see another fly nest to your right. Get rid of it, then jump to the ledge it was on. From there, you'll need to jump across a gap to another ledge. Deal with the fly nest on this new ledge, then jump right. Finally, head through the door located below you.

This room is just a small passageway. There's nothing to interact with or collect here for now, so just keep heading right to the next area.

You'll encounter a wall in front of you. Shoot it away to clear the path. Now, crouch down and keep shooting while crouched. This will allow you to collect another Missile Tank that's hidden just out of reach when standing. After grabbing that, head right. You'll soon come face-to-face with a familiar giant worm creature.