Super Metroid by Nintendo for the SNES, released in 1994.
This game should need no introduction - Super Metroid is one of the most beloved action games ever created for any system. 16 years after release, it is still topping many gamers' favorite charts.
Following on the heels of the original Metroid (and its underappreciated sequel), SM set out to do more of what made those games great; give the player a huge world to go exploring in, with several weapons and tools to pick up. These would be required to access the deeper levels contained therein.
Nearly a decade passed between the release of the original and this update; what had changed? For one, the "pass key" system was gone and graciously replaced with save points as in the GameBoy version. Also, no longer would the player need to make his own map, as there was a very helpful auto-mapping feature which would make it much easier to maneuver throughout the game world.
Of course the audio and visual elements received a major upgrade, the previous incarnations of the game were quite spartan in their presentation. Super Metroid was carefully crafted to be a spooky, mean, alien-looking experience unlike any other played before.
The rhythm of the earlier games was smoothed out as well, and the whole game just flows a lot more cleanly. You move from goal to goal in a very nice progression, and many of the frustrating moments of the older games are replaced with a lot of "oh, gee" moments instead. Few games, if any, have ever been so masterfully paced as those in the Metroid series.
There's a reason that this is considered such a plateau in game design, and the title holds up impressively today. If you are one of the five people in the world who has never picked up this game, I recommend you do so now - however, I am in the minority that still prefers the original 8-bit predecessor, as it is that much creepier and more gratifying, ultimately.