Disclaimer: I can't vouch for the accuracy of these comments. I haven't seen the episode yet myself, so blame the people on 2ch if any of this turns out to be wrong. Also, I'm not going to bother translating the comments on the seiyuu, because many people on 2ch have been biased against the cast changes since the moment they were announced and it's all a matter of opinion.
Young Hohenheim appears in the beginning of the OP!!! And his hair is color-traced YES!
Isaac makes his departure in the first episode. So it seems he's just a guest character after all.
The first episode is an original story. Chronologically, it's supposed to take place before Lior? Al mentions that they had bought train tickets to Lior but had to cancel. Lust's dialogue apparently indicates this as well. So do they go to Lior in the second episode?
Characters who appear in the first episode: Ed, Al, Roy, Hughes, Riza, Bradley, Kimbley, Armstrong, Gracia, Elicia, Father, Lust, Gluttony. Winry and Hohenheim make no appearance. Father has no lines. Gracia & Elicia's voices seem to have been changed?
Ed and Al meet Hughes for the first time in the episode.
The visuals that go with the ED are unexpected in that they are Ed & Al's scribbles moving around. (Sounds cute!)
"I'm of the opposite view of everyone who's saying the OP's visuals were really great. It made me feel like saying, ehhh? The song fits Hagane, but the song and visuals don't match very much. The part where the First Lieutenant and Winry are lying on a bed and moving their mouths to the lyrics was kind of erotic." (....whut)
Ah, so the OP shows Hohenheim growing up. Guess there's no confusing the non-manga readers then. XD But...why show that so early? Hohenheim himself doesn't really become relevant until way later on in the manga...
Apparently there are a lot of gag scenes, with the characters becoming super-deformed like in the manga. The Ed-is-short jokes are a bit overdone?
So, that line from one of the commercials where Roy yells "Don't make light of my flames!"? That's from a humorous scene in the first episode, where Roy is drenched in water and made useless. Then at the end of the episode, he catches a cold and sneezes.
"Number 23 -> Trisha -> the young brothers -> Hohenheim in the present
As the brothers stand in front of flames, the title appears
-Entering the A melody
Present Ed blowing in the wind, present Hohenheim standing in a grassy plain, present Al lying sprawled.
-Around the B melody
Young Ed, Al, and Winry looking cute
A scene of young Ed's arm and leg taken away and young Al getting his entire body taken away
-High point of the song
Ed VS Lust, Gluttony, Envy
I think Greed and the Fuhrer might have appeared briefly too.
Scar in the dusk and a smiling Pinako and Den are inserted in the middle
Silhouettes of young Ed and Al as their shadows stretch out
Oh, and somewhere in the middle, for an instant there was Hawkeye and Winry in different places with their arms hiding their eyes and just their mouths lip-syncing the lyrics.
It was sexy and made my heart jump"
-There are two rounds of fighting against Isaac, the first one ends when he escapes from the police
-Isaac is one of Mustang's war buddies
-Isaac seems to have realized the homunculi's plan
-Mustang's ignition cloth stock is in an attache case and he uses that to melt the ice
-Hawkeye tells him "Please don't become useless when it's not a rainy day"
-When Hughes shows up, Mustang's reaction is "...Here comes the annoying one again"
-The Elric brothers meet Hughes for the first time. They stay over at Hughes' house.
-The quiche that Gracia makes apparently taste similar to the ones Trisha used to make
-Bradley seems furious at Isaac
-Bradley says "I have something to brag to my son about" (smile)
-Mustang catches a cold near the end
-Lust mentions "Lior"
Sounds like they're throwing in a lot of foreshadowing for the plot and identities of certain homunculi~ I think I like what they're doing with the Isaac story...it's nice that we get more screentime for Hughes so early on. :D
I will keep updating as I find more. 8O
EDIT: A TV special just aired that showed some more new scenes. My thoughts.