Samus's upgrades will allow her to access new areas.
In the game Samus's suit will become a vessel that can transport the Light of Aether back to the Luminoth Energy Controllers. It will also be a translator that allows her to open some Luminoth doors. She will update this translator several times over the course of the adventure.
Samus's standard Power Suit, built for her by the Chozo, is made stronger by this upgrade. Provides shielding in battle and increased physical strength. It's life-support systems allow her to survive in water and space without additional equipment.
Once Samus receives this upgrade, she will be able to resist the atmosphere of Dark Aether to an extent. Dark matter attacks and extreme toxins will still injure her.
After Samus returns all of the energy to the Luminoth Energy Controllers, she'll be able to fully resist the elements of the Dark World, as in the atmosphere of the world and the extreme toxins will not injure her.
Even better, the Light Beams placed throughout the game are now useable. For example, the Luminoth Energy Controllers will be used as teleports between the areas for faster movement between them.
The reason as to why this is a "Light Suit" is "made from the pure light from the Luminoth Energy Controllers", as explained by the Luminoth in the game.
You will find new weapons over the course of the game, each required for success. There is an ammunition system for the Dark, Light, and Annihilator Beams. You will need to collect light and dark ammo in order to replenish supplies and reuse those beams.
Opens purple hatches. Hinders enemies, extinguishes light crystals, and is effective against Light Aether enemies. Charge to fire an Entangler blast, which enshrouds enemies in shadow.
Opens white hatches. Can pass through enemies and set them on fire. Can be used to energize light crystals and is effective against dark enemies. Charge to fire a wide-dispersing Lightblast that will continually burn enemies.
Fires streams of energy that seek out multiple targets and emit sonic waves that can be used on sonic-powered devices. Effective against light and dark enemies. Charge to fire a Disruptor shot that stuns enemies.
Press to fire. They home in on targets and blast open red hatches and Brinstone impediments. Missile expansions are scattered across Aether, and each one will increase her Missile carrying capacity by five. Every beam has a charge combo that can be used with Missiles to fire powerful blasts that open certain hatches. Samus has to search for these upgrades. When found, select the appropriate beam, and press while holding .
Fire and home in on multiple targets at once. While holding , use and to move the reticule to lock onto a maximum of five enemies or targets it passes over. It is also possible to lock onto the same target five times.