By now you've probably got the hang of the layout of Brinstar, as much of it's layed out in a similar fashion to the original Metroid's map. But don't get used to it as this ain't your normal remake, and the map system has new surprises. Exit the statue's room via the right door and descend the massive shaft you explored earlier. Descend the shaft down to the door along the right wall with no visible access point.
Shoot through the blocks along the narrow tunnel in line with the door to break through to it, then head inside. Cross this tiny room to find another tall shaft leading both north and south. See the red door right ahead of you? You'll need Missiles to break through it, so we'll need to go and find the first Missile Tank. To do that begin by descending the shaft right to the very bottom, stopping to save your game in the Save Room below the red door if you wish.
Once at the base of the shaft head right and cross the next rocky corridor to find Missile Tank BR.01 sitting atop a pillar. Did you notice the screen shaking violently as you entered this corridor? Head back to the left door to find yourself accosted by a giant centipede creature, the "Deorem". Check the bosses guide for hints to take this irritating bug out.
If you manage to kill the beast this time around, grab the Charge Beam it drops before leaving. But if it escaped you'll fight it again later on for another chance to get the Charge Beam so you haven't missed out. Go back into the tall shaft and climb up to the red door. One Missile will do, with the door open go inside and cross the following corridor.
Watch out for the annoying bugs flying about in here and don't step in the acid pits. Below the next small room lies Missile Tank BR.10, but it'll be easier to reach once you've found the Power Grip. Moving right along, in the next cavern you'll find two bug nests blocking your path. Shoot them down with your beam and don't forget to pick up Missile BR.02 before leaving.
Cross the next small room to find another large corridor where you'll find Missile BR.03 right at the entrance. If Deorem survived the previous encounter you'll find it in this corridor waiting in ambush. Finish off the monster once and for all to pick up the Charge Beam, then move on to find Energy Tank BR.01 atop a pillar. Enjoying the item hunt? Well, you've only hit the tip of the iceberg so there's plenty more to find.
Beyond the door at the right end of the corridor you'll find a shaft leading both directions. Drop down below and break through the red door to find Brinstar's Map Room. With the map downloaded, ascend the shaft as high as you can and go left. Straight ahead in this small shaft you'll find a Save Room, once you're ready go left at the top of the shaft. Roll through the narrow tunnel ahead in this bluish corridor and blow through the red door ahead to finally track down the Bomb upgrade.
Before leaving be sure to pick up Missile BR.04. We'll now go and find the next Chozo Statue (it's optional by the way, you don't need to visit all the statues). Back in the bluish corridor you'll be sealed in as the doors lock themselves. Go over to the pillar near the right door and bomb it open to release a bunch of small parasites hiding above the pillar.
As they hit the ground keep laying bombs before they gang up on Samus. Once all the bugs disappear the doors will unlock. Go back down to the shaft and backtrack down the long corridor. Once back inside the room to the left of the corridor where you found your first Energy Tank, bomb through the floor and descend the short shaft. Head left and blow through the red door at the end of the corridor (watch out for the herd of Wavers) to find the statue waiting patiently inside.
Jump on the hands and activate the Morph Ball to be shown where the Ice Beam is located, in the northern expanse of Norfair. Continue backtracking down to the corridor where you first encountered Deorem and head right. Bomb through the wall barring your path and proceed right to find an elevator in a small chamber beyond. Ride it down to enter Norfair's fiery caverns.