Metroid (1986) on NES—the cartridge in all its gray-plastic glory.
This is my favorite Nintendo franchise, the very reason “Metroidvania” is even a word. Not a Miyamoto joint but a Yokoi production, and you can feel it—tougher, sharper, with real bite. Few games of that era had this much atmosphere, this much mystery, or were simply this fun.
Honestly, it’s probably the biggest reason I still keep an NES hooked up.
Castlevania 2: Simon’s Quest follows the formula. Unlike the first game, Simon’s Quest is an open world game with lots of backtracking. It has experience points, shops to buy things, and puzzles to solve by using key items in the right locations.
The game also features upgradable whips, secondary weapons to find, and even a day/night cycle.
Metroid didn’t pioneer the progressive tool-based unlocking system anyway though. The Legend of Zelda was built on that concept and released before Metroid (in Japan; in the US Metroid was released a week before LoZ, but both were a year after the Japanese releases).