|“||Heat level critical. Life support failing.||„|
Extreme heat, heat or high temperatures is a common obstacle throughout many games in the Metroid series. The temperature rises to extreme levels, and thus, will damage certain non-heat tolerant creatures, including Humans. In the case of Samus Aran, her basic Power Suit's life support systems will begin to fail if she is exposed to extreme heat, and either has to run through the heated area quickly or wait until she can arm herself with the Varia Suit, which negates heat damage.
|“||Intense heat readings detected behind this door.||„|
Often, when Samus Aran enters a lava-themed area, she will be consistently damaged when exploring most rooms in it. In most games, the damage is five energy units per second, but Metroid: Other M is more forgiving in that only one unit of Energy is lost, because Samus will be forced to go through superheated rooms in Sector 3 / Pyrosphere until she gets to the top of the Crater Interior, where Adam Malkovich will "conveniently" authorize activation of the Varia Feature.
In Metroid: Zero Mission, superheated rooms will be marked on the map in orange. When stepping into one of these such rooms, there will be an orange hue shadowing most of the screen. Barely any superheated areas are featured in Zero Mission's Norfair, but this changes in Super Metroid, as almost every room is hot. A mirage effect is usually used for superheated rooms in Super Metroid and Other M, but no effect is used for the Prime Magmoor Caverns at all, except that before Samus gets the Varia Suit and encounters heat, her Visor will glow an orange tint, and water will condense on her Visor. In Metroid: Samus Returns, a remake of Metroid II: Return of Samus, superheated rooms are indicated by a red glow from the doors into them when they are open, as a warning not to enter unless the Varia Suit has been acquired.
The Varia Suit/Feature is only good for stopping damage from hot atmospheres, and is not capable of protecting Samus from actual lava, or heat-based attacks. She will have to obtain the Gravity Suit in order to completely stop or reduce lava damage.
Metroid, Metroid Prime Pinball and Metroid Prime Hunters, while all containing lava areas, do not feature extreme heat as an obstacle. The lack of these areas in Metroid would impact Zero Mission, as there are few of them in that game, allowing the Varia Suit to be skipped.