Okay, continued analysis. First off.
Someone on Tumblr translated the song in the first trailer. I completely misheard the English part of the lyrics, so there goes anything I guessed based on that. But the lyrics are interesting. Probably not what a lot of people who have posted in this thread expect. You can view the blog for the Japanese lyrics but here are the English ones:
I want to destroy
Will you be able to heal me from loneliness, from pain
And all things I had cherished
(Reincarnation, Realization, Reincarnation)
I want to disappear
Sounds of a city that never sleeps, the melancholy of these fake smiles
These real motive hiding, someday, somewhere as we had never seen them
Even if nobody speak about things as insecurity, we know about it
I want to destroy
These courageous acts I had cherished
But then, I won’t be able to be honest
Even if I’m lost or in trouble, if you ever ask me,
At least, I’ll destroy this pain and this loneliness
(Reincarnation, Realization, Reincarnation)
I want to reincarnate
That certainly points to a dramatic story, although not necessarily in the same way as people wanted. The song probably sets the tone for Kiria's character since she's the singer. We also hear it at Kiria's concert in the Treehouse video, which seems to be the start of the plot. So perhaps it sets the tone of the entire game. "Reincarnation" seems to be the title of the song, so it's probably an important concept in the game. I suspect that it's referring to the characters being reborn as the creative person inside. I'm wondering if maybe that concept ties into the Iconosphere, like that world is spawned by people's creativity of hidden desires or something.
Anyway. Onto the trailer proper. Let's start with the mechanics. Looking at the character select screen, you've got Strength, Magic Strength, Dexterity, Speed, Defense, and Magic Defense. Stats growth appears to be random like Fire Emblem. Pretty standard RPG fare, doesn't seem to be drawn entirely from either series. There's another thing below those stats though, and I can't figure that out. Insteaad of being a number, it's one of five words. It's not class or element, since those are represented elsewhere.
Here's a screenshot if you want to examine the stat screen.
Mirages have their own slot beside the player and what appears to be an experience bar. Does the fact that they have their own slot suggest that you can switch them out? Their experience bar doesn't go up after battles, but I think that's because the Treehouse demo has them maxed. The Treehouse people mention at one point that they're stronger than normal or something along those lines. And if you look at the top right outside of battle, you see Chrom's face with "enemy info". So presumably it's an unlockable ability for Chrom, but they wanted to show off the elemental system. Since there's only one displayed on screen despite every character having a Mirage, perhaps you can only have one active ability.
If it ends up that Mirages can be switched out, then there might be demon fusion and stuff like that. But I think it might actually be possible to include permadeath for Mirages, too. I mean, if you have spares and most of them aren't important to the plot, why not?
Probably doesn't need to be said, but it looks like the weaknesses do work the same as Fire Emblem. For example, Pegasus Knight is weak to bow and wind magic, but resists dark. So it should be a lot easier to predict an enemy's weakness at a glance than in Shin Megami Tensei IV.
Regarding the overworld. This was probably clear, but it's interesting that the implementation differs slightly from Shin Megami Tensei IV since attacking an enemy doesn't trigger the battle. It was mentioned by the Treehouse people that you can escape from an enemy after stunning them, but I suspect there's also a little extra risk now. An enemy can sneak up on you while you're trying to get a sneak attack on another one.
In battle, there's a "tactics" option which is separate from the "skills" option in the battle menu. My first thought is that it would just collect miscellaneous rarely-used options like guard or escape, but those are on the wheel too. I don't think it was shown off in the Treehouse presentation. Only Itsuki seems to have it. Instead, other characters have a "change" icon, which shows two characters with arrows in between. I guess it's to change turn order?
Whenever the session attack list pops up, you can see that it has three fields: holder, name, and risk. Holder shows the characters who are participating in the combo. Name shows the skills that they're using. What's risk? It wasn't mentioned in the demo either. Unless I missed it, there's never anything to the right of the skill name. I guess it's a game mechanic that only appears later on. The name suggests some kind of penalty.
Here's a screenshot if you want to look for yourself.
There's autobattle if anyone cares. It's not on the wheel though, it's on the bottom right part of the screen. Maybe the tactics option is to set AI routines. Oh, and you can see from the save menu that the demo is being played at normal difficulty. So obviously there must be multiple difficulty modes.
There's a poster with an electric superhero guy seen in a few places in the early game. Look at these screenshots. I suspect that it's the tokusatsu franchise that Toma wants to act in. I think that Eleonora, the blonde girl, can be seen in an early poster too.
Here's one screenshot,
here's another,
and here's another. The Eleonora poster's on the top right of the first screenshot.
The villains in the red cloaks are probably just a reference to how Fire Emblem represents enemies with red. Notice how Itsuki and Tsubasa both have blue hair like Fire Emblem heroes, and Itsuki also wears a blue jacket. But the red cloaks also remind me of the Shaman class from the GBA Fire Emblem games, as well as the Ring of Gaea cultists from Shin Megami Tensei IV.
I can't help but point out that when Shibuya is invaded by the Idolosphere, it doesn't look anything like that apocalyptic scene from the first trailer. There's no physical damage to the area. I'm wondering if there's another threat that comes up later. The beings from the Iconosphere being Mirages, I wonder if they're aren't actually illusions, unable to affect the physical world. It would fit with the "Illusory" in the title. Then there could be something else that causes the physical damage to Tokyo.
When they load the second save file, you can see that Itsuki's wearing different clothes. They're still casual clothes though. Maybe your characters change costumes as the game goes on, maybe there are costume options of some sort.
Some parts of the Shibuya 109 dungeon has a gothic lolita vibe to me. The antique fences and such. The music's a bit on the creepy side. I'm wondering if it's just this one dungeon that has that atmosphere. Are the dungeons in Persona meant to be unnerving? As an aside, each of the different floors of the dungeon actually has a different floor design. It's a neat little detail.
Some more details that might be missed. Chrom has the Falchion, but he only uses it for his dual attack. The explosion that appears behind Toma after he transforms is totally a Super Sentai thing. And those silhouettes that are always walking around are often carrying things that suggest having varied ages. Some have suitcases, others have backpacks, and a few have purses.
Well, that's what I found. Can't wait for Gamexplain.
