Heat is an obstacle you’ll come across fairly early on in Metroid Dread. As soon as you get to Cataris, the first thing you’ll notice is a door that has a red glow emanating from it. If you try to go in there, your health will immediately start to drop, as your Power Suit can’t cope with the overwhelming temperatures rapidly.
So how do you deal with the high heat? To move around these rooms without taking any damage, you’ll need the Varia Suit. The sole purpose of the suit is to protect you from heat damage, letting you tackle those zones you couldn’t before. The suit will be a bit of a challenge to get, and you’ll need the Morph Ball ability before you can even get it, so make sure you take all the steps necessary to unlock the suit. The suit also increases the strength of your melee attack while you’re moving.
There’s one important thing to note, though: the Varia Suit won’t protect you from taking damage while in lava. You’ll typically only find lava while in high heat zones, but if you only have the Varia Suit, you’ll quickly start taking damage again. There are several challenges involved in maneuvering through lava, some of which you can do if you’re quick enough, but if your energy level is low, it’s better not to try.
If you want to move throughout lava freely, then you’ll need to find the Gravity Suit first, a late-game item that sports a stylish purple look for Samus. Once you have it, you can return to those high heat zones filled with lava and finish off those challenges, most of which won’t be too difficult with the improved suit. With the Gravity Suit in hand, any temperature-related issues will be washed away, and you can breeze through the entire map.
