I wrote a small guide for new players: https://pastebin.com/ULNp3dv0
The vast, starry horizon at the title screen coldly glares at the player as the sharp radar pings remind you of the graveness of the mission: To navigate a mysterious, desolate planet and find and eliminate Mother Brain who has the designs to reproduce the deadly metroids - large, parasitic airborne aliens able to feed on the very essence of life, and whose biology represents the very danger for all of galactic civilisation. A chilling introductory sequence like this is something that has never been encountered by any player before, and immediately signals that precaution and wonder is at the turn before you press the start button. This game is so much beyond an adventure.
Many things have been written about "Metroid", and at the time of its release I truly consider it had been the greatest game ever made. It's an adventure that goes beyond Zelda's
previously organised set of dungeons, and instead you only have one big world to get lost in, where many of the points are immediately inaccessible until you get the necessary technical upgrades, in a game genre since called a 'metroidvania'. With a free-form and open setting like this, it becomes chill and relaxing to play "Metroid". You don't feel like you're in a hurry and you can take your time getting intimate and familiar with the large caverns of Brinstar and Norfair, as they become places you will revisit countless times and where upon mastery you'll be able to thrive in them.
"Metroid" is a pioneer for expanding the action platformer gaming far beyond its perfect jumping-and-shooting mechanics. It is a vast, imaginative world with alien, organic imagery and highly detailed pixel art. The sprite art for the tall, grim statues, the metroids, and Samus' walking and running animation were all peak for the Famicom's development, and the ease of controls and the endless stocks of identifiable secrets, with there being a secret passage at nearly every corner, make it immediately addicting and something you can't put off playing, a hallmark for any quality game. If you come here fresh from completing the first "Zelda", you will now the importance of bombing suspicious looking walls, floors and ceilings, and when a dead-end has more than meets the eye.
You really do have to exercise caution and have resources available to you to cushion your journey. The manual offers a basic map that you can expand upon, and I recommend any player to document and draw their own, because you'll need to know the spots you bypass or need to revisit, and the secret entrances you find. Many of the game's corridors are intentionally designed to be mazes that will throw the player out of the loop, as you encounter so many corridors that are literally copy-pasted for space constraints, and are placed just in front of the boss entrances to try to divert you from finding them. Sometimes you will find dead-ends. Sometimes there will be spots in the game where you can get easily stuck and sometimes you'll have to get crafty to reach unreachable areas. Being prepared for these things with the manual, map and guides does get you the tools you need to surmount these obstacles, but the one truly big blemish I have to fault the game for would be the lack of any complete health refills. That every start of the game begins at low health and that you have to farm enemies for it to build it back is simply unnecessary, when a game like Zelda just a few months earlier included complete health refills in fairy fountains. Although farming is in its own way meditatively enjoyable, it just takes too long and happens too often for it to really synergise with the playing experience, and is therefore a reason why I really recommend people play this with save states or rewind - or one of the third-party hacks.
Fighting the dreaded metroids at the end and facing Mother Brain in her sterile, white, smooth metallic chambers with way too many deadly organisms bubbling in the vats and multiplying, is at once punishing, surmountable, and rewarding. It is a challenging mission. Once you defeat Mother Brain and are treated to a wonderful ending complete with a cinematic, sci-fi infused scrolling credits sequence, you will be left itching for more Metroid, and that's when the game's replay value really gets to shine: Speedrunning "Metroid" gives different types of endings, and finishing Metroid in under two hours is, in a sense, a good exam to demonstrate just how much you've learned about the game and how much you've mastered it. With its eerie locations, the triumphant leitmotifs of Brinstar, and the ever-deepening sense of oppression as you find the lairs of notorious enemies, and always a hope for a game-changing power-up just around a corner, "Metroid" is a mesmerising experience and far from a game you would play once and abandon.
I got the best ending, too.