Metroid Prime 2: Echoes

Metroid Prime 2: Echoes is, as you may have guessed, the sequel to Metroid Prime. It's also a somewhat polarizing game – while it's acclaimed for its complex puzzles, excellent boss design, and greater difficulty over its predecessor, it also introduces a useless and somewhat annoying beam ammo system plus a dark world that's entirely too successful in its goal of creating an atmosphere of dread to the exclusion of enjoyability.

Still, it's Retro unchained, a game hitting the highest highs and the lowest lows of the Prime series. It's also absolutely packed with unused content.

Airthorn


Technically this is used, but only in one room in the Dark Agon Wastes (the enemy's early name outright states it's for Sanctuary Fortress, via the common prefix "Digital") where you can't interact with it or scan it. It's a fully functional enemy which doesn't appear where it's supposed to, and which is only seen as decoration behind a Morph Ball tunnel.

Others
As seen in the scan data lists, there were a lot of enemies that didn't make the cut. Unfortunately, with the exception of the Airthorn, all that's left are the namedrops from the lists. Most of these are darklings and Prime 1 rejects; there are a couple totally unique ones, though. Many still have unique scripts located in RelProd; they might be possible to load in-game.


 * Bacteria Swarm - no clue what this would've been (Light World Ingstorm?), but has a script.
 * Chozo Ghost - from Metroid Prime. Not on any of the scan data lists, but has a script. Presumably cut earlier than even the Elite Pirates and other things limited to the older scan data list.
 * Dark Metaree - presumably cut when the Metarees themselves were. May have morphed into Dark Shriekbats before being cut.
 * Dark Pirate Aerotrooper
 * Dark Shriekbat
 * Dark Sporb - the Power Bomb Guardian in the final game is a darkling Sporb, and may be related to this removed enemy.
 * Dark Triclops - presumably cut at the same time as the normal Triclops. Probably uses the Triclops script like the Mechlops does.


 * Elite Pirate - from Metroid Prime. Wouldn't really make sense in this game, with the reduced focus on the Pirates due to their low-resource operation. Probably turned into the Ingsmashers, which behave similarly to the Elites, having the same body structure, destructible shoulder-mounted cannon, and similar animations. This is lent credence by the fact that the Ingsmashers are nowhere to be found on the list with the Elite Pirates, but are added on the list where they have been removed. Furthermore, ElitePirate.rel is still present among the enemy scripts; there's no script for the Ingsmasher.


 * Kenobite - mechanical versions appear in the final game as the Mekenobite, but the presumable organic basis is nowhere to be found. It can be assumed to have behaved much like the Mekenobite.
 * Metaree - the armored Skrees from the 2D games. They have a script. May have morphed into Shriekbats, which lack their own script; however, it's just as possible the two similar enemies shared it, like the way many of the darklings share scripts with their normal counterparts.
 * Metaree Swarm - apparently, Metarees were also considered as a swarming enemy. Swarm has a script, too.
 * Minirees - with babies, I guess. May have morphed into Shriekbat Infants before being cut.
 * Shriekbat Infants - would have been available for both Shriekbats and the tougher Metarees.
 * Stone Toad - has a script.
 * Triclops - has a script!
 * Zoomer

It's also worth noting that there was a form between the Chykka adult and Dark Chykka, during that boss fight, known within the game code only as "Chykka 3".

Removed Weapons

 * Annihilator Bomb
 * Dark Bomb
 * Light Bomb

All three are namedropped in the old Research/Inventory scan data list, and included in the one that's actually used in-game! They're listed next to the Power Bomb, in the same order as the beams. No information is left on how these might have worked; no data of any type exists other than their presence on the lists.

Unused Multiplayer Powerups
In Metroid6.pak, unused text strings exist for the following:

Absorb Attack lost!/Absorb Attack acquired! Dark Shield lost!/Dark Shield acquired! Light Shield lost!/Light Shield acquired!
 * Absorb Attack
 * Dark Shield
 * Light Shield

Unused Lightbringer Behavior
ZHlbbpnNlGg Lightbringers are an "enemy" which act as mobile Light Crystals. Quite useful. However, the only ones in the game disappear after getting the Space Jump, before getting any of the alternate Beam weapons.

Despite this, using glitches to skip the Space Jump reveals that Lightbringers have unique reactions to all three Beam weapons! The Light Beam supercharges them, and the Dark Beam nullifies them, just like the normal crystals/beacons. However, the Annihilator Beam destroys them, a behavior unlike the standard crystals, but which is actually mentioned in the Lightbringer's scan data! They drop an Ultra Energy when destroyed; you can also use a charged Dark Beam shot to freeze one and fire a missile at it. This behavior would suggest that the Lightbringers were intended to see greater use than they wound up getting.

Emperor Ing Oddities






The penultimate boss of the game, the Emperor Ing, has a few discrepancies in its final phase which suggest the fight was to be a much more complex, strategic affair than it wound up as.

Further exposure to Phazon has mutated the Emperor Ing. It is now capable of shielding its vulnerable areas with energy barriers. Beams of opposite polarity can damage these barriers, however. Heavy damage to these barriers will cause them to drop, exposing the creatures weak spots. Target the weak spots to immobilize and damage the enemy.

This text from Mutated Emperor Ing's scan data mentions it putting up barriers around its weak points, of which there were multiple. The description suggests you need to switch beams to match the barrier color at the moment, and destroy the barrier before letting loose on that weak spot...but there is nothing like this in any phase during the Emperor Ing battle.

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However, If Samus performs the Screw Attack at a tiny area of space just behind any one of Emperor Ing's five feet, it will take massive damage. It has no reaction to being damaged in these locations; it just continues moving, and no barriers are put up. Some data remains in the game which suggests how the fight would have worked.

There are empty Ing "eye" sockets at the joint of each leg. A piece of concept art in the Image Gallery reveals that these were intended to have fleshy orbs matching the color of the core in them, which were presumably the barriers. It can be assumed you'd have targeted and destroyed these (thus breaking their barriers, and leaving the empty sockets on the model) before attacking the weak point they protected. An unfinished, untextured model is present in metroid2.pak, with the Emperor Ing's used geometry. It's a small, irregular lump, similar in shape to the Inglet's eye but substantially larger, perfectly sized to fit into the sockets present on the legs. It's probable that this was the model used for the "eyes" there.

It should be noted that the game handles damage to these weak points and damage to the core differently; if the Emperor Ing is damaged using one of the weak points on his legs while the core is any color but red, and beam damage is dealt to the core after this but before it changes color, all of the damage dealt through the old weak points will be completely recovered. This means that the game keeps track of the damage dealt to these weak points separately, which suggests they were to be destructible. The code allowing the Emperor Ing to heal in this situation probably has something to do with the barrier color switching.

Early Luminoth Texture


The "dark" Luminoth texture seen in an early trailer (explicitly stated to in fact simply be an early design) is still present on the disc. The layout is similar to used Luminoth textures, but the entire thing is, oddly, an absolutely tiny 128&times;128 in resolution.

Removed Music
e3-landing.dsp escape32.dsp Moth-Temple-open32.dsp mp-puzzle.dsp multi-defbgm-speed32.dsp pirates_kyu.dsp recharge.dsp Ruminas-after32.dsp

An early listing of the game's streams present on the disc references eight tracks which are not present in the final game. Many of these seem to have been replaced, as pirates_kyu.dsp is nowhere to be found but pirates_kyu-3-32.dsp is on the final disc and is used. It stands to reason that pirates_kyu.dsp would have been a predecessor of this track.