On the NES Metroid title on this game, you can make your enemy spin around rapidly in certain conditions. To do so, make sure the enemy is one that affixes itself to walls (such as the spiked foes in Brinstar), and make sure it's crawling up a hatch. Next, shoot the hatch without striking your enemy and the enemy will spin around rapidly in midair. This will give you about five seconds to slay your enemy when its defenselessly spinning around, with no danger to yourself. Unfortunately, however, this technique doesn't work on bosses.