In the original version of the game, Samus' death animation was a bit different. As her Power Suit breaks away from her, Samus appears to be completely nude underneath it, and she lets out an agonized scream before she dies. The combination of the nudity and the scream was deemed too sexual for American audiences, so Samus was given a two-part bathing suit during production, and the sound was muted. Contrary to popular belief, the uncensored animation has never been seen in any version of the game, not even in the original Japanese release.
First game in the series to refer to the Chozo (the original bird-like race inhabiting Zebes) by name in the game's manual. Their statues were seen in-game in both Metoroido (1986) and Metroid II: The Return of Samus (1992), but were nowhere identified as of Chozo origin at the time. According to behind-the-scenes stories, the Japanese manual of Super Metroid made references to "chojin-zoku", meaning "bird-folk race", but this was misinterpreted as "chozo", which means "bird statue". The word Chozo was subsequently chosen as the name of the race depicted by the statues.
The trivia items below may give away important plot points.
The ending where the baby Metroid defends and sacrifices itself for Samus would later be referenced in Metroid 4 (2002): with Samus nearly dying during the fight with the Omega Metroid, the SA-X parasite allows Samus to absorb its core upon its death, regaining her most powerful abilities which she then uses to defeat the Omega Metroid.