Vael Fight:
This is the “Final Boss of NGS”, apparently.
And…you’re just basically dumped with others into a floating square area where the comms don’t work very well. It’s an MPA, you can only do the fight live with whoever else is online at the time. There’s no story, there’s no lead up as to how your guy got there or anyone else for that matter. Crawford/central command tries to call you and etc but they also never explain.

2 ‘squid like’ things attack by slamming the ground, flailing, sending out beams, and creating explosions. When you defeat these, Vael will appear, and it’s like some long snake/dragon thing with 4 ‘arms’ that have blades on them, a strange crown that floats above the head, and tons of spikes/teeth. It’s scary sure, but it’s not “A dude” which was what was very deliberately presented earlier (in the blue goo) that ‘busted out’ and attacked everyone. There is NO EXPLANATION as to why this snake thing is here, why there’s a crown, why it’s not the dude from earlier…nothing. It's big, like 300 ft. long or something too, of course it can also fly around/go anywhere..

The comms start up again, and you go to Nameless City, but up in the air above it because the Vael is flying around somehow, so they send you MARS with infinite battery to battle it. Now, you have to chase it around while it spins out rings of…something you can’t touch, spins the blades, does homing attacks, lasers, the usual bit. A character (random) will “call in” during the fight and bestow a power up of some kind upon everyone. Glen, Crawford, etc. will give different boosts and auto restasign replenishment for this part of the fight. Wearing it down enough will cause it to summon a ring of swords around itself. You have to destroy all the yellow orbs in these to prevent a mega-attack that fills the whole area.
When that’s prevented, you get put back on the square boss arena without MARS, and it’s back to battle as usual where it tries to smash you with the arms/blades, summons ‘attack bomb’ things that you have to destroy (to prevent the big attacks) and then once its hit enough it dies. It DOES talk, but it’s largely unintelligible, perhaps ‘you die’ or something.

It summons a big ball energy attack, but you get a golden coated MARS (In a cut scene) and are able to blast it up and out of the dome of nameless city which is then revealed to be a ship from PSO2. Out in space it dissolves into an energy ball, and you flash back all of the characters where Aina and Manon say "let’s go to our future". Doing a big chop with the MARS cuts through this purple stuff that it has made, it shoots out homing purple cubes/lasers which you dodge while standing on the MARS. A mouth beam hits your MARS and breaks it, but you have enough forward momentum to get to the face and kick/stab it to death. It goes into that ‘purple/red starburst’ shape that starless do when destroyed.

Once it dies, it has like that red…explosion kind of diamond shape and the screen goes black.
Then, white screen appears, and you can hear Ran, who asks about the reading, another confirmed? He self destructed the data…you wake up in space, kind of in a golden light that is upon you. You remember the explosion and look all around to see a ship REALLY far away. Reaching for it, the character loses the golden light and starts to die in space. It goes black until you hear the voice of Zephetto, who says
‘don’t give in’ the Venogia Mech Suit is behind you, "The world to come is going to need you".
He grants you a bright blue glowing power. Aina and Manon frantically look at screens in Nameless City where they are, because your character has apparently dissappeared/gone off the map to them/Crawford as well. Something happens, and they look up to see a sparkle in the sky, they chase it to see that its your character that’s falling down, at first curled up, then open to use the flying. It lands on the street of Nameless City and they come running up.

Aina is so happy you’re alive, but Manon asks what was that light? You look up to where it was, but nothings’ there. Aina suggests going back to report to Crawford, and everyone does. The scene ends.

You’re summoned to the Command Room AFTER you fight the MPA boss “And The Stars Fell”. This was actually expected to be fought as part of the story, but you only go there with the online team/strangers whatever. (Expecting a team of like Dozer, Aina, Manon etc to go & have explaining dialogue, but because it’s MPA everything is extremely minimal like ‘oh comms are out fight this thing idk’.)

When you get there, Manon and Aina are also there, and Ilma and Crawford are waiting. Ilma says what happened after the Vael fight? The comms cut out after a big explosion and Ilma thought ‘it was all over’.

I think…maybe Zephetto saved me
I’m not sure myself

Well, both of these are true. Something very Zephetto like was out there, and even your guy asks if that’s who it is. So, if you speculate with I Think Maybe Zephetto Saved Me, Ilma is surprised, so is Crawford, and everyone looks worried. Crawford says you’re too shaken up, so lets talk when you’re feeling better. (SO. They don’t believe you- it is clear.)

How Are Things Over Here?
What Happened To The Starless Assault?

The 2^nd one is more likely to be direct/get better answers so What Happened to the Starless Assault?  Crawford says the regional ARKS defenders came together, so they supported you guys, and Vael is no longer a problem. Oh yes, the guy who wiped out billions of people is now 'no longer a problem' because like 400 guys shot all his minions in the face in 1 afternoon and 1 single guy took him out after he turned into a giant snake with 4 arms and was then defeated by just 1 dude with a magic sword. Hm. Bogus.

Aina wants to ask, if we’re done fighting the Starless? (She’s very sad/stressed)
Ilma says we’re not quite done yet. He was the overlord. Zephetto told the truth about that, but they didn’t stop just because they lost their brain. Crawford says it’s not over yet, but 1 major threat is behind us. Aina is very sad, Manon is mad at this news.

I’ll Find A Way To Handle This
We’ll Be Fine As Long As We’re Together

Who knows what the way even is at this point? These nerds can’t even turn off the dolls after all this time, your one guy isn’t going to find some off-switch. If you say “We’re Together” , they brighten up and say it’s true, we’ll keep working together. Aina and Manon nod, and the scene ends.

Now the credits roll.
So, this is being presented as a pretty definitive end to NGS.
Obviously ‘more to do’ is in there but like.
After the credits it says “To Be Continued”

WOW this is an ENTIRE non plot thing that just happened. What the heck is the explanation for any of that? Why was Vael some weird dragon thing with four arms that kind of screams unintelligible words, it was like the entire end boss and it just dies and that’s it?
Why did Zephetto think it was a person? WAS it?
It feels like there’s a whole huge cut scene missing from between “Zephetto appears from Pharia one last time” and “The big boss comes out”. How did anyone get there to where the big boss is? There’s too many questions, it’s just missing too much stuff.

Unanswered things that were set up on purpose:
What is in the core of Leciel?
The Nameless City is shown to be one of Xiaos’ city ships but it’s empty
Why can we not turn off the DOLLS?
Who saves ‘your guy’ when it is ejected out into space with its MARS to whack Vael one last time to finish it off? It’s clear that ‘your guy’ is dying until something happens and it gets shoo’d back to Nameless City the Ship to meet Aina and Manon. It is implied that it is Zephetto, or his Venogia System (did it only partially break?)
Ghost of Garoa keeps showing up, are they showing ghosts are real here for a reason? What is up with him, he appears to you but not to his own kid? DOES your guy see him or not?
Why are the Starless so LAME?
THIS bunch of low grade mooks killed GOD????
Are they serious? Xiao, while not having the powers of Xion, is still seriously pretty much a god. Vael and the starless are pushovers compared to the stuff they faced in PSO2. There's no way in hell they'd have been able to take out the ARKS, even if they got really 'lame somehow' for not fighting big threats for 500 years or whatever it is. Being able to teleport instantly he could have knocked them all into the sun 1000 times in 1 minute. Xiao didn't fall off the training log (even if literally every single other person did--he doesn't age, he never forgets, he always improves, and he can be everywhere at once) Also, being thrown into the nearest star WOULD have killed them all, because being chopped by a MARS scythe weapon killed Vael pretty much and that is nothing compared to a star.

They built the starless up to be This Big Thing, and then they were a bunch of low grade enemies and a big snake who got killed by being stabbed by 12 people with energy swords. There's no way he/they lived up to the hype of terminating the ARKS and their kid-god-computer all those years ago. Unless he had some sort of unseen/undisclosed instant-vaporization power which he clearly does not because he didn't use it here.
Obviously "the plot" has to take a back seat to the "gameplay" of a literal game so we can't go turning off the starless or the dolls because then the game has no monsters to fight.

Opinion Zone:
Over all, it did pretty well. A lot better than some of the PSO2 chapters.
There wasn't a ton of plot to it, but they did wrap up most of the loose ends that they deliberately introduced (except what's in Leciel Core, what was Vael's actual deal/why was he such a threat then and not now) The characters all stayed in-character, nothing was incredibly annoying or non-sensical, the plot didn't wander off and the ending was 'good enough'. It DOES need that 'to be continued' though because we do need to see what about the rest of the story of 'your guy' and get to the point of them being able to turn off the monsters--but it's fine to leave that for the next part of NGS.
Their mistake was hyping up the Starless as much as they did, and crediting them with feats they'd never have been able to accomplish in-universe unless there's something huge missing. Not getting the story off of Halpha particularly leaves not much to entice more plotting is also possibly an error. Zephetto was really cool but he could have used to stick around more rather than just showing up and dying right away. It felt a bit rushed at the end, like there needed to be plot between Zephetto Dies and Vael comes out, something to explain him more/set up how he came out or how Vael was nerfed or Zephetto Lied about how strong the Starless were because they don't make sense being this weak.