The following is an in-depth guide for the first area of Metroid.
Once you're dropped in, you'll immediately be introduced to the first enemy, the Zoomer.
This enemy takes 2 regular shots to defeat and one missile shot to defeat. Go to the left and jump over the wall to get the Morph Ball. Just press down on the d pad to go into a ball to roll under ceilings. Keep heading right to find the second enemy, the Skree.
You can dodge it by just running past it. You'll also find a Red Zoomer soon after, which is the same as a regular zoomer except it takes 4 regular shots to defeat. Keep heading right and shooting through the blue doors until you reach a wall. Use the morph ball you've just obtained to roll under it. You'll then find a Reo.Keep heading right through the door to enter the first Brinstar shaft. Keep jumping up
It'll swoop down and it'll stay down until you jump past it, so just jump over it.Keep heading right through the door to enter the first Brinstar shaft. Here, you'll find Rippers.
You really can't defeat these, so just make sure you can't bump into it. You'll also find a red varient, which is basically the same thing. Keep jumping up and go through the first blue door on the right. Then go through the corridor to go to the right to a second shaft. Head all the way to the bottom and go to the right through a door. Here, you'll find a new enemy, the Zeb.
This enemy is great, because you can just have one continuously coming out as you shoot it to grind for health and missiles. There are a few different colors, but the only difference is the amount of health they have. Keep going right and you'll find the missile items. This can be used to one hit most enemies, or get through specific missile doors. Go back to the left through the door, and go up and through the first left door. Then, go up and through the first left door you find again. Make you're way to the left end of this hall to get to a red door. This takes five missiles to permanently destroy. Inside, if you shoot the orb, you'll find a Long Beam item. Previously, you're shot disappeared after being in the air for a moment. Now, the beam will go all the way across the screen. Go back to the right into the shaft. Head south and through the right door. Keep heading right through two more doors to enter a new area with a new enemy, the Waver.
These guys go up and down in a wave like pattern, so they are pretty predictable and easy to shoot. They are also very small and easy to dodge. Keep heading right, you'll pass through two narrow hallways on the way. You'll eventually find an Energy Tank. This adds another 100 energy to you're maximum health. Then, head all the way to the right until you find a vertical shaft. Head up and through the first left door you find. Go all the way to the left and through the red door to find bombs inside. You can place them by pressing B while in your morph ball. This can break breakable blocks or attack certain enemies. Go back to the right to the shaft, down to the left door. Go all the way left until you find a narrow hallway with a small ceiling. Use bombs on the middle of the floor to drop inside past the sand. Go down to the bottom of this shaft and through the left door until you find a red door. Inside, you find the Ice Beam. The Ice Beam will freeze and unfreeze any enemies you shoot. This is extremely useful, and even required at some points. The only problem is that it takes twice as many shots to kill enemies. This is barely a problem though, even though it seems like a big issue. Go back up to the low ceiling hallway you were at earlier. Go all the way to the left and through to the shaft. Go back up and through the right door when you come to it. Go to the right in here, rolling into a ball and going into pipes when you need to. Eventually, you'll reach a low ceiling hallway, similar to the one you found earlier. You can come back once you have the High Jump boots, but if you want it right now, then here's what you have to do. There's a spot where you can shoot through the ceiling. Get the Waver in here through the hole in the ceiling, then freeze it once it's in there. If you do it right, then the Waver will fly into the room above. Then, shoot the ground and jump so you land on it to get up there with the Waver. Then, you can freeze it again to reach the top of the cliff. Then, go to the left to reach the Varia. The Varia makes Samus takes half the damage she took previously. Go back to the low-ceiling hallway and keep going right. When you reach a dead end, shoot the ceiling, jump in and go right. You'll have to place a bomb to boost you up pretty high. To gain some extra height, spam the B button while holding right to get some extra bomb height. Then to the right you can find an Energy Tank. Finally, go to the section right before the low ceiling in the first part of Brinstar and shoot the ceiling to find an energy tank. You can use the ice beam to get up there. From this spot, go right to the first shaft, go up and then right through the doors to the second shaft. Go to the very bottom of this shaft and go to the right here. Then go all the way to the right and through the door to reach an elevator. Use this to reach Norfair.
Next: Norfair