The original Metroid introduced us to Planet Zebes, an enormous, self-contained world teeming with things to explore. At the time, it was a new approach to action games, eschewing the old stage-by-stage setup. The problem was that the NES's hardware limitations made every room look almost exactly the same, which took away from the game greatly. Fortunately, Super Metroid improves upon this - Planet Zebes is back, it's much bigger than before and now it's a sight more interesting, with four enormous continents, each with its own unique atmosphere. This may well be the first time moody ambience was successfully portrayed in a video game - it's created by the dark coloring, the excellent music and even the sound effects. What's more, the theme of exploration is still just as present as ever, every little corner of Zebes being packed with items, some of which allow access to new corners and worlds. The planet contains enemies aplenty, but none of them are particularly difficult (even the bosses, while intimidating, aren't very challenging) - it's the exploration part that gives the old brain its exercise.
The series' protagonist, bounty hunter Samus Aran, returns for her finest hour (and last hour, at least for seven years). One of the first female video game protagonists ever, Aran probably remains the best - at the very least, it's good to see a woman traversing unspeakable dangers, yet dressed appropriately to the task at hand. That brings up arguably the best part of the game - Samus's androgynous-looking spacesuit is extremely versatile, and the variety of moves that can be done with it combined with possibly the best play control ever seen on the SNES makes for a hell of an engaging experience. Samus runs, jumps, somersaults, swings from ceilings, soars through the air, curls up into a ball and rolls around, uses a wide assortment of firearms and explosives, and generally kicks ass with style. Oh yeah, the game even has a plot. Granted, it's pretty cheesy, but it's there, and it's just about as much as a good action movie needs to still be good. Add to this the moody ambience, the great graphics that succeed in providing a sense of otherworldliness, a painstaking attention to detail (the cherry blossoms gently falling to the ground in Brinstar are a great touch), a fine soundtrack (the Brinstar theme sports a hook any musician would do well to steal), and a huge, finely woven maze of a world, and you have yourself one of the best action games of all time.