I just finished the demo after watching a certain YT video and dfjhgfhjf as soon as this game comes out I definitely intend to buy it when it does! I can tell you've put so much time and thought into just the demo alone and honestly as an aspiring indiedev myself all I can say is I'm impressed by how much is in this small (i'm guessing very small, for that matter?) portion of the plot (not to mention how much eventing and scripting you must've done for just this section of the game alone!)
I'd have to say my two favorite parts (past Archie who is just naturally great and I love his dialogue about plants with Lily - kind of hope that becomes a running gag between them ngl because that scene built up perfect relationship chemistry between those two as well as w/ poor Perry) would be the jewelry shop and the scene with Daphne you get to see as Archie.
I wandered into the jewelry shop out of mere curiosity, quickly realizing that the guy could move between shop counters. When the guy complained about me not making up my mind and wheezing to the ground, exhausted, I couldn't help but snicker and be in complete awe of that scene. It's such a small detail, almost insignificant because you're not required to visit the shop during the demo whatsoever, but it honestly brings your game to life in a way that tells players you're rewarding them for their curiosity.
I also loved Archie's intrusion into the scene with Daphne scolding the train crewmembers. Being able to watch that optional cutscene that I stumbled upon by mere happenstance while exploring such a small town was truly a treat in of itself. It's made even better by the small details like the guard going back to constantly fix the suit of armor, trying again and again to fix it only to just meekly give up and hightail it out of there.
I also found that Archie's comment on getting out of there a nice touch: especially since I realized later that his behavior up until meeting Lily (such as hiding behind the train as Daphne escorts the crew members away) made sense, especially because he thought he would get in trouble and was trying to avoid that. It also made me wonder though: does Archie have some intrinsic fear of authority figures and/or being punished for acting too out of line? Much of his behavior suggested he was avoiding directly confronting any authorities because he didn't want to get in trouble, and I'm not sure if that's because he didn't want his message delivery to be interrupted or because of some maybe past trauma (such as having the authority figures in his homeland threatening him constantly for speaking out of line which results in an unease to be found by authorities and accused of making trouble). I can see him going both ways but I suppose I'll have to wait before I can learn more about him to see if I'm right or wrong about what I noticed about him
Lily and Perry were also good, their comedic timing is well paced, though they felt a bit generic for characters compared to Archie. Lily in particular fell a little on the generic side, mostly because girls who love art kind of feels like an expected stereotype in stories (and this is coming from someone who actually is that stereotype irl so pot meet kettle lol). It's not bad in any way as long as she's given other unique traits to make her stand out (like comparing art tools, perhaps, or getting in a heated debate with Archie over the identification of various flora). However, her love of plants and her distraction by them in comparison to more important events does make her pop out more. It was really refreshing to have a character be so into plants to the point of distraction, even being exasperated at Perry for not knowing what type of plants they were (which correlates with his mentality to have the plants be a stepping stone to show he's responsible: he doesn't care what kind of plants they are, only that they show his dad he's worthy). You had a really good dynamic there as I mentioned before and I would love to see more scenes like that, with Lily and Archie getting distracted and Perry hauling them along as some sort of running gag (kind of like what you've already shown to be doing in the comic you gave glimpses of).
Also in regards to Perry: his options to ~bully~ Flint were really satisfying as a player to pick and I loved his opening scene (as well as his "for the love of- WE'RE CLOSED" shtick that happens constantly throughout the story (the poor customer at the end though...I laughed at that so hard lmao). He feels a little bit on the typical hero side, but with that said there is something endearing about him that makes me feel at ease even with that knowledge. His comedic timing really sold him and I can only imagine him being at odds with the jargon Archie and Lily might use on discussions about plants or even leaving them behind if they're too absorbed in their own little worlds.
My only nitpicks I would provide, aside from that a quick skim through the comments below has suggested, is maybe increase the timer on the train. For me, even though I'd watched the YT review of this game, it took me quite some amount of time to talk to everyone in the train AND figure out who to talk to to trigger the cutscene to get past the Sentinel guarding the front of the train. By the time I'd found the sick guy my timer was 0:03 which, supposing a Bad End is implemented if one goes over the time limit, might be frustrating to players if they have to redo going the whole entire first scene again (especially if they didn't think there was a point to saving because obviously the puzzle is supposed to be doable in five minutes).
Also, speaking of save files, I'm not sure if this is just an occurrence on Mac computers or if this is just a built in feature of the demo (especially considering how relatively short it is), but I was unable to save during the length of my play session. However, I only tried saving once (iirc in the town playing as Archie) so it could be that I was only preventing from saving in that location but could've saved elsewhere.
Other than those flaws (and the ones I've seen other people already mention which it sounds like you have fixed already :Dc) this was a really amazing game! For such a short session, I found myself connecting a lot of dots to potential plot points (and what might happen after the demo's ending) but that doesn't at all stop me from wanting to buy this when it's done! From what it sounds like, this is going to be a lengthy game (especially if there are...7? 8? realms to go through and we've only ever seen a town in one of them) and I'm definitely eagerly going to be awaiting the day this arrives in full to play!!