Not the best in the series but one of the best Game Boy games.
The story is a sequel story. That's for sure. The Galactic Federation has deemed the Metroid species too great a threat for civilation and in order to prevent any further incidents, has sent the only person whos knows enough about to their home planet. The legendary bounty hunter Samus Aran. The overall mission is simple: Go to SR388, exterminate the last wild Metroids and get off the planet. Like the first, you have to read about the story and the rest is gameplay that doesn't progress any further until the end, which you will be very satisfied with.That's a worthy sacrifice though, considering the times and the evolution of gaming.
The gameplay is same as last time. Run, gun, search and destroy. What's different and more helpful is the counter showing the Metroids left. But where the game really fails is the background design. Most of the walls and caverns are monotonous and repetive, filled with rocks and bricks, making it harder than before to navigate through the maze that is SR388. But like before Metroid is a hard series to navigate through since there are more secret places than believable. There are new power-ups, though, making combat easier throughout the game. To name a few, the Spider Ball, which lets you crawl up walls and celings in morph ball or the Spazer Beam wich shoots your beam in 3 directions like a shotgun. The ones from the original show up too. The enemies seem to just float around and aren't very well designed either. The Metroids are very detailed, though with evolution cycle they go through. They seem to grow from floating jellyfish-like creatures into massive floating reptile beasts. The fights are very challenging and you must get missles to defeat and to move on with the game. Another thing that can be said is that compared to last game, the save system is much better. The password system has been replace by save stations scattered throughout. But the stations have a price of their own, being very hard to find and usually in secret areas instead of on track.
The music isn't as good as the original, but there are few good tracks here and there. There's usually a slow, steady beat or beat that seems too upbeat like the main theme, which is different. Overall it's a great game on it's own merits but doesn't quite regain all the things that made Metroid so successful.