I found the secret energy tank in Kraid’s room in Metroid by using two maps: one shows where every suit upgrade, missile upgrade, energy tank and boss room is, and the other is a complete detailed map of the Planet Zebes, including the location of every destructible block. Getting the energy tank is kind of a difficult maneuver in itself. Instinct tells you to fall into the acid, shoot the destructible block that hides the item with your beam weapon, then jump back onto the main platform, enter morph ball mode and roll into the newly-exposed crevice. But the angle you leave the platform at means you just miss the mark. The solution is to jump to the right once you have exposed the block, to the ledge of the room’s entrance, then enter morph ball mode, fall down and hold to the right so that you can slot in. All of this I discovered through Google, which directed me to a GameFAQs thread where other people have agonised over precisely the same problem.
This wasn’t possible back in 1986 when the game was released. You couldn’t outsource your problems like that, pulling solutions from the web’s vast pool of information. You had to consult vague strategy guides in magazines, ask for tips from friends and relatives, keep notebooks filled with passwords, encyclopedic notes, make crude maps with your own reference points. Back when I first got Metroid from the eShop I had planned to play the game this way, rejecting the easy answers from the internet and exploring the game entirely by myself, edging forward piece by piece, feeling my way through the darkness. Zebes is a bewildering, open-ended labyrinth, and demands to be treated as such.