The next installment in the Metroid Series is Metroid II: Return of Samus. Utilizing save states and the portability of the Gameboy brought this game a lot of success after it's debut in 1991. The developers at Nintendo took the original metroid to a whole new level with this title. They overhauled the graphics and gave Samus a very human-like appearance. She was taller and her suit had much more detail.
The story followed Samus through the caverns of SR-388. A small planet which is home to her nemesis, the metroids. Her task this time was to destroy every last one of the creatures and therefore force them into extinction.
Althought limited by the greyscale technology of the Gameboy, the sound continued to excel. It had less of a soundtrack in this edition and more of a context based background noise. Music was not constantly playing, yet the sounds of the creatures roaming the dark caves made up the soundtrack.
Metroid II saw the release of more interesting upgrades to Samus' suit. She could now jump in her morph ball and had more beams at her disposal. The game still did not feature a map and this title is arguably more confusing than the last.