All There in the Manual: The Nadia Audio Drama CD not only explicitly confirms that the other man in Nemo's holographic portrait is Gargoyle, but that the portrait was taken the day before Gargoyle initiated his coup.
Art Evolution: Nadia's Mother's character model has been redesigned from its preceding cameo appearance in Episode 16.
Art Shift: Electra's flashback sequence. In retrospect, one can see the beginnings of Evangelion's own experimental animation sequences here in this segment.
The Atoner: There have been hints here and there, but now it's explicitly confirmed Nemo is indeed one and trying to fix the damage he helped unleash (between failing to stop Gargoyle's coup to nuking his own homeland) 13 years ago.
Continuity Nod: When Gargoyle activates the Tartessos Tower of Babel in the flashback, the activation noises are the same ones from the test firing of the Cape Verde Tower.
The Coup: Gargoyle pulled one on Nemo 13 years ago.
Driven to Suicide: Electra tries to do this in the climax when she learns that Nemo does care about her. Nemo intervenes and talks her out of such behavior.
Dramatic Irony: Grandis' 'The Reason You Suck Speech' against Electra in the previous episode turns out to have been within striking distance of the truth.
Engineered Public Confession: A variation. Jean accidentally turns on the Nautilus intercom in Nemo's cabin after they hear Electra's gunshot. It connects to the Bridge intercom, allowing the children to hear all of Electra's confession and revelations. Electra doesn't realize she's had an audience listening in this entire time until Nadia begs her not to shoot Nemo. It's also not clear if the rest of the ship heard the confession (though it's implied they heard some of it from the Chief Engineer's appearance during Elektra's breakdown).
The mechanical noises and Neo's emotionless, almost robotic tone of voice hint he's a cyborg. This is also foreshadowed in the very specific shots of the metallic gleaming of his royal accoutrements.
Similarly, it's strongly implied Neo was a Puppet King for Gargoyle 13 years ago (and that this relationship hasn't changed in the Present Day). There's even a shot of Gargoyle's mask 'smiling' during his transmission, hinting that Gargoyle is treating this serious conference call with his sovereign as if it were a private joke and a performance.
There are subtle clues that Tartessos is the site of Blue Noah, such as the Tower of Babel and its technology being directly integrated into the city's structure.
It's very subtle and not explicitly invoked, but there are hints even this early that Gargoyle was Nemo's Prime Minister. The coup targeted and killed the Queen, which would've required the rebels to get inside the palace and deal with Nemo's bodyguards and security. This suggests Gargoyle had insider's knowledge/help. Gargoyle was also able to corrupt Neo, which is doable with young kidnapping victims or prisoners. But, it's also infinitely easier if, say, a malleable young lad already knows you and might think of you as an Honorary Uncle. Finally, Gargoyle knew how to access the Tower of Babel and how to use its systems — all specialized information that someone like a highly-placed governmental official would be able to get their hands on.
Nemo's reaction when the Nautilus command module becomes caught in an undersea current. With the reveals of the closing episodes, it's obvious in retrospect Nemo's formulating the plan to try and ride the current to one of the surviving underground Atlantean tunnels.
Gamechanger: After having served as the primary setting and plot generator for a dozen episodes, the Nautilus is destroyed and the three heroic factions (the Main Group, the Grandis Gang, and the Nautilus crew) scattered across the ocean (and with the fate of the latter two left up in the air).
Hell on Earth: The week in which Tartessos was destroyed was described as this by Electra.
Heroic BSoD: Electra's continues from last episode and goes full throttle.
Hope Spot: An unintended Meta example. From this episode, you'd expect that shit has gotten real and that a grand and glorious climax is about to kick off. Unfortunately, next episode marks the beginning of the dreaded Island Arc and the downward plunge until Anno returns in the closing episodes.
I Know You Know I Know: The first thing Nemo tells Electra when she shoots him is that he is aware that she knows that he destroyed Tartessos and that she was making little effort to hide it by the time the shooting happens.
Killed Off for Real: The Nautilus. This is the last time we'll see the original submarine.
Oh, Crap!: The younger Electra when, from a distance, she sees the explosion that killed the Queen of Tartessos. Happens again when she finds her "unconscious" brother by the lake shore and tries to pick him up... only to see his arm fall off the socket.
O.O.C. Is Serious Business: Marie is uncharacteristically silent and serious after Electra's confession and Nemo's cabin is cut loose. Even the 4 year old grasps she just witnessed something profound and life-altering.
Origins Episode: Electra's backstory is finally revealed — and with, the broad strokes of Gargoyle and Nemo's own histories.
Out of the Frying Pan: The Nautilus escaped the Sea-Net Beam Gum at the end of the previous episode, but they're still crippled and all but defenseless...and there are still more Garfish in reserve swooping in for the kill.
Properly Paranoid: During the final pursuit of the Nautilus, Gargoyle correctly concludes the submarine hasn't been torn in two by the depth pressure and that Nemo's suckering them. Justified as Gargoyle knows Nemo well and thus know how he thinks and fights.
Puppet King: It isn't explicitly stated in this episode, but it is heavily implied Neo was one to Gargoyle 13 years ago (and still it). Later episodes will definitively confirm it.
Putting on the Reich: Gargoyle's proto-Neo-Atlanteans during the flashbacks, setting the stage for what we'll see in the Present Day.
Sadistic Choice: Nemo in the backstory. He could either stand aside and let Gargoyle take over, allowing him to subjugate the world and kill millions...or he could destroy the Tower of Babel, which would devastate Tartessos and kill his people. He chose the latter.
Sinking Ship Scenario: Played with. Between the damage from the previous episode and the combat decisions Nemo has to make against the Garfish flotilla, the Nautilus is flooding and on an express trip down to Davy Jones' locker. However, it shifts into a secondary focus as the primary focus becomes Electra's betrayal of Nemo and breakdown.
Spanner in the Works: Nemo sabotaging the Tartessos Tower of Babel was this for Gargoyle (and it's one of the reasons why he hates his former monarch's guts so much). Its destruction and the loss of their homeland set the Neo-Atlantean agenda back over a decade (thus aligning with hints about the movement's rise and activities over that interim).
Surprisingly Realistic Outcome: Escaping the Sea-Net Beam Gun trap at the end of the previous episode wasn't much of a victory and doesn't do the Nautilus much good. They're still alive, sure, but they're also now crippled and defenseless and Gargoyle's throwing everything he has left onto the table just to deliver the coup de grâce.
"The Reason You Suck" Speech: Electra tears into Nemo as all her frustrations from throughout the series finally come to a head.
The Reveal: Apart from being Nadia's father, Nemo is the exiled King of the last Atlantean city-state Tartessos. He was deposed 13 years ago in a coup led by Gargoyle, but Nemo undercut his victory by sabotaging the Tartessos Tower of Babel. The sabotage destroyed their homeland and much of the Nautilus crew is made up of survivors who sided with Nemo rather than the Neo-Atlantean cause.
Uncertain Doom: The Nautilus and her crew after the children are cut loose. Whether they survive or not won't be answered until the closing episodes.
We Have Become Complacent: From Elecrta's flashbacks — and combined with further details later in Episode 35 — Tartessos was more or less this: The last Atlantean city-state and living in quiet, peaceful isolation from the larger world for 12,000 years after its parent city's fall. While it's left unclear exactly how long Gargoyle's coup was brewing (and how much popular support existed for him to tap into and exploit), the end result was all this came crashing down thanks to a rebellion Nemo didn't see coming and couldn't stop.
Wham Episode: The destruction of the Nautilus is complete and the fate of the survivors is left up in the air. Electra reveals her true colors and tries to kill Nemo before nearly killing herself. Nadia learns Nemo is her Father.
"[Gargoyle] changed the name of our kingdom from 'Tartessos' to 'Neo-Atlantis'.
"...That is, until the day your real daughter appeared before you with her Blue Water!" is an in-universe example for Nadia, who finally learns the truth of her parentage.
"No, please don't [shoot Nemo]!" is another in-universe example for Electra, who then realizes Nadia's been listening in this whole time and just heard her entire confession.
Wham Shot: Literally, with Elecrtra — Nemo's best, most loyal lieutenant — pointing a gun at him and pulling the trigger.
