Summary
Everyone’s favorite intergalacticbounty hunter, Samus Aran, has ventured to many unique worlds and conquered plenty of fearsome enemies during her travels, but she’s definitely not invincible. For most of theMetroidgames, Samus will gradually upgrade her suit and weapons throughout the story to take on any monsters that stand in her way, and whileshe can usually hold her own in a fight, there have been more than a few occasions where Samus has been caught out due to weakness.
While most of these weaknesses have been shown in-game, some have been referenced through the lore that some fans may not even be aware of. Samus Aran is no stranger to facingterrifying creatureshead-on, but if any of them were to expose these weaknesses, they might just have a chance of defeating the legendary bounty hunter once and for all.

5Her Lack Of Long-Term Powers
Despite Samus acquiring a whole catalog of unique abilities by the end of each game, she always starts her next adventure with little more thanthe Varia Suitand an Arm Cannon. Of course, this is an intentional decision to create a satisfying sense of progression with each game, but as it’s happened on so many occasions, Nintendo has actually made an effort to try and explain it within the lore, but this only ends up making Samus look weak in the process.
InMetroid: Other Mfor example, it’s explained that Samus' powers are ultimately under the control of her leading officer, Adam Malkovich, who locks them away until she’s ready to use them. Explanations like these might not be the most convincing way of going about this, especially since Adam ended up becoming apretty disliked characteramong the fanbase due to the amount of control he had over the main character, but it does also mean that Samus is seemingly incapable of keeping all of her abilities at the ready for long periods of time.

4Her Vulnerability To Ice
While Samus does receive special enhancements to her suits in many of the games whichhelp her survive when in certain climates, her weakness to ice and cold environments has always been a specific focus in more than a few entries. For example, it’s only near the end ofMetroid Fusionwhere it’s explained that the Varia suit can now protect Samus from her weakness to ice, but when switching over toMetroid Dread, she no longer has this immunity.
There are a few lore reasons why this might be the case, but by far the most convincing and the one that makes the most sense is the fact that Samus literallyhas Metroid DNA within her. She was injected with this after being infected by the X Parasite, and while this does grant her the ability to absorb the parasite for energy, it also brings with it extreme sensitivity to the cold. This is also why Samus is only extremely vulnerable to the cold inMetroid FusionandMetroid Dreadsince these are the only games where she possessed the DNA.

3Her Motherly Instincts
Despite Metroids being the primary enemies for the majority of the games, Samus has been shown to still spare some emotion for them from time to time, especially in the case ofthe Baby Metroidthat appears in several of the games. After being ordered to exterminate all surviving Metroid on the SR388, Samus eventually comes across the final survivor hatching from an egg, and after a moment of caution, decides to disobey her orders to protect the life of the infant.
Despite being very helpfulMetroid: Samus Returnsthanks to how it is able to chew its way through crystals that Samus couldn’t previously get through, the baby also ends up getting Samus into some pretty life-threatening situations. The biggest example of this is when Samus is confronted by Proteus Ridley who, in a desperate attempt to stop the extermination of the Metroids, decides to attack Samus and free the baby from her possession. Samus and the infant Metroid barely make it out of thisfrantic boss battlealive, and while the baby does play a very big part in the lore, it always proved that Samus’motherly instinctscan often come as more of a weakness when in the middle of a mission.

2Her Personal Trauma
By the time fans see Samus inMetroid Other M, one of the later games in the series' timeline, it’s made clear that Samus is suffering emotionally due to the amount of loss she has witnessed during her time as a bounty hunter thus far. Considering thatOther Mis supposed to only be set a few weeks after the events ofSuper Metroid, we can see that the death of the Baby Metroid especially weighs heavy on her conscience.
Another example of this is the appearance of Ridley inOther Mwhom she’d thought had been taken down for good in the previous game, but it turns out was simply a clone in this game. Not knowing this, Samus gets aharrowing flashbackto her childhood where Ridley killed her mother right in front of her eyes before calling the young girl “pitiful” and flying off. While this is only touched upon inOther M, volume 2 of theMetroid Mangaactually shows Samus having a full panic attack upon just seeing Ridley, demonstrating that the deep sense of loss and trauma she has experienced in her life can act as a weakness in specific scenarios.

1Her Reliance On Her Armored Suits
There’s no doubt that Samus is more than capable of punching and kicking through a few monsters without her armor equipped, especially thanks to herhigh-tech Zero Suit, but she still heavily relies on her armor to get through missions in one piece. Alongsidethe Arm Cannon, which is essential for eliminating enemies from a safe distance, Samus' armored suits are also capable of firing missiles, dropping bombs, turning into a Morph Ball, and spotting enemy weak spots thanks to the visors.
Of course, the suits can also be modified and upgraded in a plethora of different ways which ensures Samus is always well-equipped for anything that gets thrown her way, so when she does lose the suit, it makes her incredibly vulnerable and an easy target. As mentioned before though, because the skin-tight Zero Suit won’t weigh her down, she is still very agile and has her trusty blaster pistol to fend off weak enemies, but she’s still nowhere near as powerful or protected when in this state.TheSuper Smash Brosseriesdid make Samus a little more viable when using her Zero Suit mode thanks to her new rocket boots, she also takes much more damage and is incapable of firing off some of her most devastating moves when in this form.