Samus's upgrades will allow her to access new areas.
Suits
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.
Varia Suit
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.
Dark Suit
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.
Weapons
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.
Power Beam
Opens blue hatches and has infinite ammunition. Hold 
to charge and release to fire a powerful Charge Beam. Charging also engages a tractor beam effect that draws power-ups towards Samus.
Dark Beam
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.
Light Beam
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.
Annihilator Beam
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.
Missiles
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 .
Seeker Missiles
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.