This set the standard for SNES games. The best SNES game out there. If you haven't played this yet, get it!
The gameplay is great. Samus is controlled very easily. She jumps very high and as the game progresses you slowly get better and better. Patience is a big key to enjoying this game. When you enter a new area, enemies are difficult and the atmosphere can be deadly (lava) but as you find new items, those difficult enemies become easy and the deadly lava becomes nothing.
The music is dark, subtle, and by far the most original music in a video game. It fits the levels and the puzzles to perfection.
If you have a super nintendo and haven't played this yet, please give it a shot and play it. You won't get immediate satisfaction; instead you will slowly build Samus up over the course of time. By the end of the game, you can pretty much do anything and every enemy is simple.