@bkelly19the Tomb of Horrors blurb in Tales from The Yawning Portal it suggests high level characters, what do you consider high level? 10+

— Mike Mearls (@mikemearls) March 25, 2017

@AmalgamationerFor #TftYP, are these complete adventures, or just the dungeons featured in them? complete save for Dead in Thay – that one features dungeon only. #wotcstaff

— Mike Mearls (@mikemearls) March 11, 2017

@AmalgamationerSo it’s akin to things like Lost Mines or such in terms of the amount of story? that's a good comparison #wotcstaff

— Mike Mearls (@mikemearls) March 11, 2017

Getting psyched for this shindig to start! Check us out https://t.co/c5E095myPi starting at 3pm PT! #WOTCstaff #dnd pic.twitter.com/0Nq6m4K13j

— Greg Tito (@Gregtito) March 24, 2017

Get all this stuff and more from https://t.co/TQYvBAH9eQ right now. Only chance to get some of the swag I make for #DND. #wotcstaff pic.twitter.com/NxtWJGcruV

— Greg Tito (@Gregtito) March 24, 2017

Take a deeper look at the design of 'Tales From The Yawing Portal' tales from the unimportance edition
books precisely because it is seven
adventures all collected into into one
book and on top of that a number of
those adventures are classics that
people have loved for decades and so we
not only wanted the book to meet our
usual design principles for 5th edition
both game design wise and in terms of
visuals but we also had to make sure we
were still being faithful to the
original adventures and that
faithfulness was not only on the text
side but also in the art side I know
authenticate when commissioning the art
was you were looking at half the
original pieces of art or and i was
using those as references even if we
weren’t doing a frame-by-frame homage to
the original art those pieces of art
would become part of the reference that
i would send to the artist and and
sometimes it would be like well it’s
like this but we don’t want a horn
sticking out of its head we want it to
look like the fifth edition version of
that monster and we do do that in other
respects to with other adventures but
this because we were so beholden to
keeping the adventure at their core what
what they originally were and just
updating the steps and and some of the
wording so that it it felt like 5th
edition but really these are the
adventures that you know and love and so
we didn’t want to go too crazy but it
doesn’t that we had to fit into the
fifth edition the style of monsters that
we’re doing now the style of art that
we’re doing now the style of maps that
we’re doing now there were well two of
the adventures we use the original map
because those have been done by Mike sly
who continues to work with us the Giants
adventure has some maps that were done
by Rob Maserati originally and they
weren’t in the original original that we
did a reboot of it
when that happened but so those maps are
included in the books but all of the
other maps are our new original maps
updated with the 5th edition look there
were things that resonated with people
including people on our team like well
this has to be shown because this is the
thing that that I remember the most this
fight if we have to do this so there
were a lot of a lot of things like that
when we were really trying to stay true
to what people expect we you know we
want to surprise you too but but we
don’t want to go so far outside with
this particular book that you’re like I
just didn’t feel like hidden try enough
how much on yeah yeah we wanted to keep
the adventures as close to the original
experience as possible I’ve gotten some
questions oh did we redesign the
adventures to be more like a modern D&D
adventure and the answer is we didn’t
what we did is we took tomb of horrors
and it’s still tomb of wars the tomb of
war is that Gary Gygax wrote but just
with you know 5th edition stats and if
you click in a few places some
additional clarity maybe add some
additional descriptive text to make the
Dean’s wife a bit better and you know
describing a particular room and whatnot
but all of that additional work we did
is based on material that was there
originally whether it was text or
illustration we based all of these
adventures that were at the favorite
kind of coming from the yawning portals
that Shannon was telling you know he’s
the guy that’s everyone’s telling us
sorry too and you know he’s kind of a
base point so it even though it was a
challenge that there be seven different
adventures over a huge you know stretch
of time at a different world you know
they still needed to have something to
kind of escape there’s some kind of
flavor so having that they were all
coming from this tub you know that all
the ventures start here all the fairies
come here and all the great people have
come through yeah it was it was kind of
a really nice data accuracy
so nice a yawning portal is this
aggressive symbol that can repeats
itself throughout the whole book and
that was kind of a really happy accident
later Caillou to go ahead because it’s
the blue team oh yeah symbol of the
Father and on just little your shine and
anything so and and I loved how you took
that symbol and answer paging through
the book it’s easy to think it’s just
sort of like almost a rune or something
but if you then go back and you look at
the beginning of the book it’s like a
symbol of the all important#dungeonlifehttps://t.co/u7HRJrKhwO

— Todd Kenreck (@ToddKenreck) March 24, 2017

HEROEs!
On Reddit users sks_innawoods  Zathrus1 keeto has the adventure book and give some news

• new monsters
• new magic items
• Sunless Citadel has tons of characters
• Sunless Citadel is about 25 pages in length
• Sunless Citadel is at least 4 hours of play

So I found this. from dndnext

Tales from the Yawning Portal: Disclaimer

@0Generic0Kind of a silly question, but will TftYP have information on magic items found in the dungeons as well? I.e. Azan-gund yes, it will have new rules for any new items in the adventures

— Mike Mearls (@mikemearls) March 9, 2017

@mikemearls @JeremyECrawford @ChrisPerkinsDnD Can you tell us a bit about new magic items or monsters in Tales from the Yawning Portal?

— Jordan Valentine (@KeyTenavast) March 7, 2017

Fair number of them – we also include stats for monsters from Volo's, so you don't need an extra book to use Tales. #wotcstaff https://t.co/gqycK9ySIV

— Mike Mearls (@mikemearls) March 8, 2017

@undrhilany new player options besides backgrounds? not in Tales – strictly a DM book #wotcstaff

— Mike Mearls (@mikemearls) March 8, 2017

@0Generic0 @ChrisPerkinsDnDhow would the denizens of the Forge of Fury react and interact with a party of kobolds? Hostile, confused, etc? probably hostile, would probably try to capture and enslave them; trogs would eat them

— Mike Mearls (@mikemearls) March 9, 2017