Warning: The following post contains spoilers for Metroid: Samus Returns. Reader discretion is advised.

After looking at the memories and thinking of what they mean, I've wanted to post what I noticed what information they present and what I've interpreted from them. Please note that this is only my own observations and speculations; I might be wrong and shouldn't be taken as factually correct without skepticism. Also, I've made up the names to fit what we see; they're not official. Regardless, I hope you enjoy what I've tried to put together.

Memory 01: Arrival

What it shows

The focus of the shot are three Chozo that have landed from a starship. Behind them are four more Chozo investigating their surroundings. Our main trio seem to be talking amongst each other; curiously, the two on the sides have identical attire, yet the middle figure is dressed in a less refined manner. The middle figure holds a glowing orb of unknown identification.

The foreground features four creatures watching the visitors: on the left, a Chute Leech and a Moto; on the right, two of the hard-shelled Gravitts.

Besides the starship the Chozo landed with, the sky houses three other ships. They have a different design than the main ship, favoring a vertical alignment rather than horizontal. The ever-present aurora is particularly vibrant in the night sky.

One last feature is the trapezoidal pyramid structure in the back-right. These structures are seen throughout Surface and Area 1.

What it means

There's not much to analyze here besides the fact it's showing the Chozo arriving on SR388, but that blue orb is very curious, as is the pyramid structure. That structure seems to be this game's Chozo's favorite building style, as the style is seen throughout the many areas in the backgrounds.

Memory 02: Investigation

What it shows

In the front we see a Chozo gathering a yellow orb into a capsule; said orb is from a dead Hornoad and more is rising from another one nearby. Many Gulluggs are seen feasting on other Hornoads, some even lifting them into the air.

On the left, we see another Chozo investigating an orb encased in some holographic structure. Similar holographs can be seen around both Chozo's arms.

What it means

The yellow orbs are Aeion -- they can be seen emerging from dead SR388 creatures before you even have Aeion ability "compatibility" (as the game notes when you get Scan Pulse); these orbs do not fly towards Samus until she has such compability. The second Chozo is likely running some tests on the energy, e.g. figuring out its properties, potential, running simulations.

The important thing to take out of this memory is the fact that Aeion energy is not just a game mechanic but is an in-universe phenomenom that the Chozo noticed and looked into. Something interesting to note, you always get Aeion energy when you kill an enemy in the game. That means all living creatures on SR388 carry Aeion energy. Keep that in mind.

Memory 03: Industrialize

What it shows

In the front right, we see three Chozo, two of which are analyzing a couple Tsumuris and three unknown critters. Behind them is a large amount of the digging robots found throughout the background of Area 3. These robots are marching out of the large complex featured in the area, with Diggernaut sitting at the entrance; the goliath is seeming to be inspected or worked on by two Chozo. Three Halzyns can be seeing flying above the troupe.

Overseeing the marching digger bots is a squad of Chozo in battle armor with the iconic Varia Suit shoulders. They brand glowing blue shields, diamond-shaped and as tall as the Chozo themselves.

In the lower part of the caverns, a Chozo watches as some digger bots tear through the earth and uncover something that glows bright yellow, illuminating the underside of the nearby rocks and walls.

What it means

Immediately following the discovery of Aeion energy, they obviously found some potential in it and set about a massive operation. The yellow light seeping up from the ground (which comes up in later memories) is likely Aeion, which the digger bots and Diggernaut are made to dig for. Aeion appears to be either sourced from the planet itself or was initially life energy that was infused or fossilized with the soil. This energy may be part of cycle of the planet's ecosystem as it gets absorbed from the soil by vegetation, then eaten by creatures until deposited back into the planet when they die.

Memory 04: X

What it shows

Three Hornoads are in varying stages of infection from the X Parasites: pre-infection, during the process, and the resulting mutated mimic. The caverns are flooded with the X and some have taken to attack the Chozo; a couple X can be seen splatted against the warriors' shields. The X seem to glow, as seen on the various objects and pre-infection Hornoad, but the glow intensifies when the middle Hornoad is being infected.

What it means

The X, especially in concept art, have had glowing orbs in their bodies ever since their debut in Fusion. Samus Returns makes the orbs extremely prominent, even in the game model during the final cutscene. That, combined with the in-progress infection Hornoad is emitting vast amounts of yellow light, suggests the X have evolved to consume and use Aeion energy to survive and reproduce.

Curiously, all the X present in all the memories are yellow in color; there are no green X. This seems to suggest the other colors in Fusion are the colors of energy from creatures not from SR388, or perhaps are brought about from a mutation of using non-Aeion energy akin to the blue mutation.

Memory 05: Metroids

What it shows

The room is a lab with an opened chamber in the middle. The chamber is filled with strands of a green, cohesive substance. The same substance is covering the creature that is the focus of the shot:

A Metroid.

Surrounding the Metroid are Chozo scientists overlooking the product and equipment. Display monitors feature an X parasite, a Metroid, one with undeterminable text, and a last one with an object that is difficult to identify. In the background, more Metroids can be seen incubating in chambers.

What it means

It's been stated since Super Metroid that Metroids were created by an ancient civilization. When Fusion came out, it was established that it was the Chozo who created the Metroids with the purpose of consuming the X parasites. This memory and the next one are merely reconfirming what we learned in the previous games. However, the reasoning behind wanting to eliminate the X has changed. While they saw enough of a threat from X to create artificial life designed to consume them, the Chozo seemed to have primarily had the X exterminated to continue with their operations on the planet, which is especially supported in the seventh memory.

Memory 06: Unleashed

What it shows

The Chozo scientists and warriors can be seen in the background; in front of them are the chambers from the lab, opened. The Metroids are flying out and attacking the X and X-infected creatures. There are a couple Metroids with X inside their tallons and one that is actively draining the energy from an infected Hornoad.

What it means

Curiously, when Metroids drain the energy from creatures the energy is colored purple. This can be seen in the memory and in the game itself. Unfortunately, there are no shots of an X actively being consumed by a Metroid; there are only a couple just about to be. However, Samus in Fusion does not glow purple when absorbing X; she glows yellow and green.

Just a reminder that Metroids have always been known to be creatures that "absorb the energy of any life-form", even in the intro to this very game. I'll expand on this in the eighth memory.

Memory 07: Recommence

What it shows

Two Chozo stand over ground with cracks that seep yellow light. Behind them are more Chozo that are observing a spherical hologram, possibly SR388. A Chozo warrior watches the Metroids that are floating above, one of which is attacking the sole X. Diggerbots can be seen in the background and Diggernaut looms overhead.

What it means

With the aggressive X out of the way, the Chozo can resume Aeion mining operations. There's really not much more to look into this.

Memory 08: Evolution

What it shows

Metroids have evolved. Their bodies have fallen to the floor and Alpha Metroids are erupting out of them. Once tame around their creators, the creatures have gained severe aggression and are now attacking the Chozo. Two Chozo warriors have fallen to the creatures in this shot, one of which is in an Alpha's jaws and the other knocked off the side of a cliff with an Alpha chasing after them. One warrior wields a spear in defense while two more escort the overseers out of the area.

The yellow light is very prominent in this shot, once again coming up from the ground and illuminating the underside of objects.

What it means

The Metroids were never intended to evolve. It wasn't encoded in their DNA to do so, and yet their different forms exist. What caused the evolution cycle? Even if it was unintentionally put in, why does this only happen on SR388? Fusion states it's because of SR388's environment, but what about it causes the evolution?

Aeion, a form of energy only found on SR388, is the reason. This energy is so prevalent it has made its way into the native creatures; the X, which the Metroids were designed specifically to consume, used life-energy as sustenance and thrive on Aeion energy specifically. It's no coincidence Metroids were made to draw the life-energy of creatures. They evolved from the very fact they were made to consume the X.

Aeion energy has strange properties. We've seen the Chozo were able to use the energy to enhance weapons and defenses, even to manipulate time. If Metroids consume too much of this energy, their very genome changes. Since Aeion is not present on any other known system, Metroids don't follow the same life cycle. However, once one got on board Sector 1 of the B.S.L it ravaged itself on the plentiful X from the planet. Its primary food gave it such a boost in energy it evolved much quicker than it should have.

What's interesting to note is the X-infected Hornoad that has a Metroid draining purple energy from it in the sixth memory. What's likely happening is the fact that X initially only infect the nervous system (except when the host body is destroyed and the DNA is used to create a mimic). The Metroid might simply be draining the energy from the host body before consuming the X since when a Metroid drains energy from a non-X creature the glow is typically purple, as is most forms of energy that represent life-energy in the series.

There are a couple minor problems with the Aeion energy evolution theory, the first being we see at the beginning of the game a Metroid only drain energy from an uninfected Hornoad, yet it still evolves. The Metroid's previous feedings were not witnessed, though; it's likely an X consumption was simply missed as evolving after a single meal is a bit too fast.

The second issue arises during the Ridley fight. While the Metroid hatchling will give back purple energy to Samus after leeching off Ridley, Samus herself will knock Aeion out of Ridley once the first phase is over (when he lets go of the Metroid). This might be a result of Ridley eating native creatures in order to speed up his regeneration. Dealing enough damage is likely releasing the Aieon he consumed.

TL;DR: X thrive on Aeion energy, Metroids are made to eat X and absorb life-energy, they only evolve after encountering X; therefore, Metroids only evolve on SR388 because of absorbing Aeion energy from the X.

Memory 09: Seal

What it shows

A Chozo Seal is the focus of the memory, as is the purple liquid filling the chamber. Two overseer Chozo are on the podium in front of the seal. Three warriors branding spears hold back the invading Gamma Metroid while the room is filled; one looks back towards the overseers.

What it means

After playing the game and reading the manual, it is undisputed that the purple liquid and the accompanying structure are designed to seal Metroids within the planet's caverns. Curiously, other natives are unaffected by the liquid -- Chute Leeches can be seen hiding in small puddles of the liquid and after it is drained you can immediately come across native life. Only Samus and Metroids, both non-native creatures, are affected by it.

Memory 10: Plea

What it shows

Six Chozo overseers, the center's arms outstretched, are seen communicating with a new Chozo figure. The new figure's attire is simple: an ornate headpiece, draping cloak, and a plating covered arm. Their left arm is folded up over to their left side while their right is hidden behind their back. In the back, a battalion of Chozo warriors can be seen at attention.

Above the crowd is a starship with the same design as the one seen in the first memory; however, this ship's thrusters are active. On the right is a large black structure with a blue glow at the top and another can be seen in the far back, behind the batallion.

What it means

We've seen Chozo warriors throughout the memories acting as guards for the overseers; however, never have we seen this many in a single setting. The ships active thrusters suggest this battalion has recently landed. The overseers seem to be explaining the situation to the newcomer. The arrival's presence at the forefront of the battalion suggests this is a military officer. The background structure on the right appears to be similar in design to the ships seen in the first memory, but it's difficult to identify correctly.

What's likely happened is the Chozo set a distress signal and requested reinforcements.

Memory 2d / 10 (11): Execution

What it shows

When it's unlocked, the triumphant prologue music comes to an end and a distorted screech sounds. The colors are replaced by a red tint and the heavy contrast distorts the image. When it refocuses, it's a new picture that keeps the red coloration. An eerie track plays over the scene before the memory fades.

The six Chozo overseers lie on the ground, dead or dying; smoke rises from their bodies. The Chozo commander is turned towards the battalion, arm outstretched while issuing an order. Their right arm brands an arm cannon, smoking from recently being fired. The warriors continue to stand at attention, unphased by the events before them.

What it means

After the overseers explained the situation, from the X to the Metroids' creation and their unexpected evolution, the commander had them executed. There is no stable, official verification on this scene as of now. Theories range from sabatoge to civil wars and beyond.

While I find the introduction to the scene quite interesting, it doesn't make analyzising it very easy. Actually, it makes it extremely difficult because it begs for speculations to be made, whereas the logical route would suggest the commander was readying the warriors to prepare for an extermination mission. I stand by this theory and chalk up the special effects as an explanation for unlocking a secret ending.

Perhaps all of these scenes were from the eyes of a single Chozo, with the eleventh being its final conscious memory before its death. But that's nothing more than speculation.

Other items of note / FAQ

The "official" guide by Prima is not to be trusted as canon source material and should probably be debated if entries from it can even be placed under official media sections. As such, I did not consider anything the guide has attempted to claim. Some examples of why not to use this for any explanations:

In the introduction, the "History of SR388", it claims the Chozo did not create the Metroids.

"One of [the Chozo's] most significant discoveries was a small, desolate planet labeled SR388, which held a secret: a peculiar parasitic creature called a Metroid." (p. 2)

It claims that Ridley has been known as Proteus Ridley since before Samus was a bounty hunter.

"Upon reaching the Space Pirate base, she found the second-in-command, the pterodactyl-like Proteus Ridley, the one who had personally taken Samus' parents from her...After Proteus Ridley attacked her planet, she was adopted by a small Chozo clan on Zebes...The last time Proteus Ridley was seen, he was defeated once and for all..." (p. 3) "It was Proteus Ridley, Mother Brain, and the Space Pirates that harnessed Metroids for evil during Samus' first mission,..." (p. 23)