Here's my big list of first impressions from first episodes:
Classroom Crisis -- This is sort of a school SoL in space. Has a bit of a retro feel to it since everything is hand-drawn. The first episode was mostly just introduction of the setting and characters, especially the not-so-exchange-student, so hard to form an opinion yet. I really liked the last scene with the not-so-exchange-student's pragmatism giving everyone else a huge wake-up call. That plus the way they handled having to eject the engine pods and such looks like this show will have a big emphasis on realism (and the way they explain the Mars colonization setting supports that).
Aoharu X Kikanjuu -- First episode was alright, but I just can't really get excited about a paintball anime with real-gun sound effects. The main character's circumstances (basically: cross-dressing non-transgender girl) is interesting, but given how the first episode revolved around a misunderstanding that would fit in any generic Hollywood rom-com, I wouldn't expect the show to use those circumstances for anything but crude jokes, anyways.
Shimoneta to Iu Gainen ga Sonzai Shinai Taikutsu na Sekai (A World Where the Concept of Dirty Jokes Doesn't Exist) - Already discussed up-thread. Hilarious and extremely well executed. The topic might be hard to maintain this level of quality over the whole season, but they might just pull it off!
Rokka no Yuusha -- As already mentioned up-thread, I loved this first episode tons!
Akagami no Shirayuki-hime (Snow White with the Red Hair) -- Hood's Breath, people, the show has "Snow White" in the name why are you eating the apples??!!!
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In seriousness, this was a great first episode which both kickstarted the romance and gave all the necessary backstory to get the main story going.
Chaos Dragon: Sekiryuu Seneki -- Has some good ideas but the execution in the first episode is very messy. Characters teleport around between camera cuts (ie: Kai runs toward guy with a sword, guy swings the sword, Mashiro runs forward, Kai is now suddenly 20 feet away and Mashiro has instantly covered the distance to sword-guy), the dialogue has some very unnatural info-dumps, and the backstories/character information are kinda weird (ie: if only kings can make dragon pacts, how come the guy who actually is a king doesn't know what the pact entails, but random peasant girl and bodyguard do?). The setting of an island kingdom squished between two much larger invading nations could have lead to some interesting explorations of political and worldly ideas - the main character even lines up with that given his thoughts that it might be better to just stop fighting a battle they can't win and let themselves be annexed by the larger nation - but instead they just went full on invading-nation-is-absolute-evil with pointless civilian massacres and such. Finally, hard to say for sure, but the show seems like it'll be revelling in the deaths of major characters - big triumphant rock music kicks in during the first episode when it happens and they have a character sheet at the end of each episode to cross people out of. My expectations are low on this one, the ideas are just cobbled together too sloppily so far for me to get immersed in it. We'll see if that continues going forward. (Also, the dragon looks terrible.)
Ushio to Tora -- Veeeery nineties-esque looking, both in character design and animation style. First impressions are that it is about average. Probably would have been worth keeping up with in a sparser season but there's too many shows this season I'm actually excited for to keep up with this one. The Ushio/Tora duo had a couple bits of funny back-and-forth so if there's time later in the season I'll try and catch episodes 2 and 3 to see if it improves.
Gangsta -- Ah, the good ol' adult criminals-in-mafia-controlled-land setting. This was suitably grim and violent, with grey characters hiring slightly darker grey characters to kill outright evil characters, and all the usual drugs, cops, racketeering and beating up prostitutes thrown in. Depending on if/how much the episodes repeat, this might be too gory or depressing for me to want to watch it all the way through, but we'll see. Nicolas as a katana-wielding deaf guy really helps to give the show a unique difference from other shows of similar content.
Overlord -- There's some really great stuff in this one. I like the very different take on the trapped-in-a-VRMMO setup with not only it being just the one character, but also how he already has a lot of skill and tools so he can proceed straight to analyzing the situation and pushing the plot forward - with the trapped-in-a-VRMMO setup being so common already we can easily skip through all the initial leveling up and figuring out how to fight stuff with ease. I thought they did a really good job of showing the legacy of the MC's guild and having some nice, solemn moments before the midnight switcheroo - it did a good job of setting the tone and backstory without just info-dumping. Plus, the demonic avatar and the way the guild-hall is setup as a dungeon for other players to attack adds a lot of distinction between this and SAO/LH/.hack/etc. Overall, I was very impressed by all of that. BUT, then there's Albedo and that is... just no... eugh...
Joukamachi no Dandelion (Castle Town Dandelion) -- A big family of 11 that banters and argues but loves each other? Sure, that could be a fun SoL show. An eccentric king who decides his family will live in a regular house instead of the castle and who's successor will be decided by a general election between his kids? That could be a fun show, too! A family where the kids each have a different superpower and the whole family is part of a big reality show where they show them off? Also has potential! Well, Castle Town Dandelion is all of those things: the eccentric King has 9 kids, each of whom has a superpower, and they are being constantly scrutinized by reporters and the public via cameras everywhere because the kind has decided the next king will be chosen by election amongst his kids. So, already there is a LOT going on in this show, but the superpowers are mostly incidental (they don't have to fight monsters or anything like that) and just serve to enhance the drama. The main thrust of the show is that the MC (Akane, the fourth-oldest child) is very shy, so she dislikes the cameras and tries to hide from the attention of the media, but invariably ends up accidentaly attracting it.
The good:
--Akane's shyness is portrayed well: she genuinely dislikes having any attention focused on her, but this doesn't make her melancholic or incapable of making decisions like it seems to do to most generic male romance characters or Evangelion protagonists.
--The balance of eccentric elements makes for a really great, light-hearted setting.
--The family actually gets along and has good chemistry together - I'm a total sucker for an awesome family like this in a show.
BUT here's the bad:
--The last scene has what may be the absolute worst sisterly advice ever given: "Maybe if you became Queen then you could order the press to leave you alone and live quietly". They even acknowledge a couple sentences later that that probably makes no sense. Akane seems to think it is good advice and is going to use it as motivation to try and get elected... rather dumb reasoning and I hope it ends up getting reversed.
--The first episode had four different upskirt panty jokes. It's not like this show is an ecchi, they don't show anything, so why the heck would you go for that dumb joke four different times?!
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Even people who find that funny I'm sure must be tired of it after four times in one episode. I am hoping they got this out of their system and can move on to better humour hereafter (maybe they just did it 4 times because they thought if it kept happening in one episode that would be funnier, and can move on to other recurring jokes each episode???). C'mon production company, I really want to like this show...
Teekyuu s5 -- It's Teekyuu, enough said.
Durarara!! x2 Ten -- It's Durarara!!, enough said? Knowing the novels, I was actually surprised with what they did and didn't put into this first episode. They're currently adapting volume 7, and I thought they would more explicitly setup several of the storylines in this episode, then execute them all over the next two or three episodes, but instead they did almost all of Izaya/Rio/Manami and Shinra/Celty's bits and hardly touched the other storylines yet. Doesn't make a significant difference, really.
In any case, volume 7 is sort of like the Hollywood Arc from last season (which was volume 4) - it all takes place in a single day or two and is mostly self-contained. I'm hoping they'll keep volume 9 short and manage to adapt all the way through volume 10 in this cour, as 11-13 could definitely use a whole cour on their own, and 10 would make a great ending point for this cour.
For the casual fans, volume 8 is where they really start to bring story points and characters from the first 6 chapters back around. Might be worth reading a few episode summaries for the first season to remember what happened back then. Maybe the most important bit to recall would be:
(Durarara, season 1, episode 12)
Well, there ya go, that's my first impressions. Still a few more shows not listed there that I will check out, but they are low priority ones. Charlotte I've decided I will probably wait a bit before starting - I find it hard to get fully immersed into "feels" shows week-to-week if I've got too many other shows I'm watching at the same time so I think I'm better off saving Charlotte for all at once or at least doing it in bursts of 3 or so episodes.