Ride down the elevator to be greeted by two gargoyle-type statues at the bottom. You're now in Norfair, the fiery and lava-filled region of Zebes. We won't be taking on Ridley here yet, instead it's time to go on a lengthy and dangerous treasure hunt - they don't call this an adventure game for nothing. Drop down below the elevator to find two doors leading off from both walls.
We'll find the missiles through the left door on the way back, so go through the right door and cross the lava-filled corridor. Watch out for the enemies in here, they'll take a beating, but you can also freeze them to get by. Once at the end you'll find yourself in yet another giant shaft leading up and down.
Climb up the shaft, the first door you'll reach leads to the second Ice Beam in the game, go in and grab it again if you want, but in the same room you'll be able to break through a hidden passage to find a corridor leading off on the left. Go through and climb the shaft you'll find. Cross the next corridor to eventually find two Missile Tanks, then keep going right to find yourself at the top of the long shaft leading down. Blow open a hole in the right corner to drop down below, then head through the first door on the left below to find three Missile Tanks.
Once you've found all the missiles, go back to the shaft and drop down to the bottom. From here you can find two missiles through the door on the left. You'll need to cross through a dangerous corridor filled with enemies, and you'll also need the Ice Beam to reach the missiles, but you should have it by now so that won't be a problem.
Head back out to the main shaft once you've found the missiles, then bomb open a hidden tunnel leading down in the right corner. Down below you'll find an almost bottomless shaft leading down, but you'll be looking to head through the first door down on the left wall. Through here you'll find a corridor leading to a red door, so blow it open with five missiles. Inside here you'll locate the High Jump Boots, but the treasure hunt is far from over. Go into the small opening below the statue and bomb open a hidden tunnel. Go left and bomb your way through the walls to find a new room filled with orange blocks. Freeze the enemies flying about to reach the high cliff, then eventually you'll reach a door beyond the lava on the far left.
Go through and head past the narrow corridor to find a cavernous area filled with lava. Keep going left, but watch out for the red pods on the ground that spew out lava rocks. In the next green room you'll spot a door straight ahead, jump up to the ledge above you and shoot open a hidden tunnel leading up in the corner. Jump up above and go through the door there. Cross over the lava in the next corridor and shoot open the door at the end with missiles. Go inside to find the Screw Attack, a really handy item that'll save you a lot of time and hassle. Once you've found it head back down to the room below with the two doors.
In this room, if you go left you'll eventually wind up directly below this room, so to make it much easier on yourself, blow open a secret tunnel leading down just in front of the right door and drop down. You'll land in a room identical to the one above, head through the door on the right and cross over the sea of lava. You'll eventually reach a solid wall, bomb your way through and keep going right. Once you reach a door head through to find yourself at a dead end - or is it really? Of course it's not a dead end, bomb open the ground directly below the blue bubble of the door to make your way below the fake lava. Down below, go through the door on the left and cross the lava in the next corridor to eventually locate an Energy Tank.
Once you've grabbed it, leave and head back up to the green room containing the two doors on either side. Once you make it back there, instead of going back up, go through the door on the left and cross the lava in the next long corridor. In the next shaft, instead of climbing up, we'll be entering a new secret area. Drop down into the lava at the bottom of the shaft (don't worry, it won't hurt) and you'll fall straight through it. Bomb open a hidden tunnel in the left corner of the small pit and drop down to find another long shaft leading down. Go through the door at the base to find yourself in an incredibly long corridor filled with lava and crumbling blocks dotted everywhere. First, go all the way to the right end of the corridor and you'll eventually find a Missile Tank at the end.
Once you've found it, head back left until you reach a small room with lava below the platform (You'll also spot one of the fire-breathing dragons below). Bomb open the block directly below the left door and drop down below the fake lava. Go through the door at the bottom of the shaft and cross the next corridor. Blow open the door there with missiles to find the Wave Beam weapon inside.
We've now only to find a few more items before leaving. Go back up the shaft and continue travelling left. You'll eventually reach a small room similar to the previous green rooms, this room also shares a hidden tunnel in the ground near the right door, so bomb your way down. Drop down the hidden shaft and go through the door on the right to find two Missile Tanks hidden in the next corridor.
It's now time to leave, at this point you should have found everything in this area of Norfair, so you'll have to retrace your steps back up to the long cavern filled with lava leading to the room with the orange blocks. Just remember that the large green room where you found the Screw Attack hidden above contains the door leading back to the long lava corridor.
Once you reach the orange lava-filled corridor, keep going right, past the room with the High Jump Boots, until you reach the massive purple shaft leading up. Once there, climb up the shaft and head through the second door on the left wall. Cross the long sea of lava in the next corridor, you'll then reach the main elevator leading back up to Brinstar. Before you leave however, go through the door on the left below the elevator to eventually find two more Missile Tanks.