Metroid Fusion

Explore the alien world and deal with X parasites during the run. After gaining some special abilities you have the power to proceed in the very depths of the enemy territory.

The X parasites are terrible creatures, that enter your nerve system and make permanent changes to it. That story already happened to your character, so the revenge will be fast and merciless. Get back to the place you have already been to and deal with all alien species you meet.