It's not a very substantial collection, but it's not without interest. It comprises four or five short episodes that altogether add up to just under an hour, based on side-story chapters by Arakawa that weren't part of the main manga. They're in the Book in Figures (Blue/Red) and the Perfect Guidebooks.
The DVDs I bought also have sixteen two-minute Four Panel Theatre gag extras that are actually quite funny.
1. THE BLIND ALCHEMIST
An example of this show's willingness to do horrible things to the kind of target that other adventure shows might normally consider off-limits. It's a sombre, gentle horror in which everyone is kind and no one did anything wrong. Appalling, but heartwarming.
Also an example of how Alphonse seems fated to be the plaything of small girls.
2. SIMPLE PEOPLE
It's hard to call this a story, as such. It's more of a character vignette, in which we see how a conversation between Winry and Riza Hawkeye affected both of them. It also has comedy squabbling between Ed and Winry.
Goodness me, Winry's eyes are huge.
3. THE CHRONICLE OF TEACHER
Hehehehehe. Izumi. It's Izumi.
When Izumi was eighteen, she was sent into the mountains to survive in the snow with nothing but a knife for protection. Because she's Izumi, this led to a legend of a freakish snow demon that terrorised the local military outpost. We were told about this in the main series, but here we see it.
To be honest, I was a little disappointed. I'd wanted a full-length movie or something. However it's a laugh and it has a cool punchline, so I'm very happy to have it animated.
WARNING: this is two episodes in one. Don't turn off the DVD on seeing the closing credits, because there's another, even shorter Izumi episode tacked on afterwards. This shows us Izumi's first meeting with her husband-to-be and it's funny.
4. YET ANOTHER MAN'S BATTLEFIELD
The darkest and strongest of the four OVAs. This time it's Roy Mustang's turn to have a flashback OVA to when he was eighteen. We see his military training days, getting to know Maes Hughes and defending an Ishvalan trainee from bigots and racists.
We then jump forward a few years to the Ishvalan War of Extermination.
This story is addressing all kinds of issues, from despair and guilt to a soldier's coping mechanisms for dealing with those feelings (or perhaps failing to). Furthermore they're good people fighting for evil. They're frontline soldiers in a war of genocide. When asked by one of their victims why they're doing it, their only answer is "orders". Well, that and a bullet, obviously.
Tomoko thought this episode should have been longer. I liked it a lot, but she thought it deserved fleshing out to a full standard anime episode length. That's probably a compliment, though.
At first I assumed that these were based on the four-panel omake gag strips that Arakawa puts at the end of every manga volume. They've been done in the same style, with scribbled art and silly parodies of key story points, but as it happens only a few of them are adapted from the manga originals.
They're also funny. (Very very silly and mercilessly taking the piss.) It's possible to watch your way through all sixteen in a row, which actually takes a surprisingly long time. You might not expect that gag-based style of comedy to hold up, but it does. Tomoko also tells me that some of the jokes are Japanese pop culture references, e.g. to Gundam.
For goodness sake, though, don't watch them until you've finished the series. They charge through the entire thing in order from beginning to end, lampooning key scenes and hence being full of massive spoilers for anyone who hasn't watched it yet. (Just as importantly, they wouldn't be as funny if you hadn't seen what they're parodying.)
These OVAs are fairly throwaway, to be honest. They're all little side-stories, or else going back to fill in the gaps. You don't need any of them. However they're also quite a good cross-section of the show's qualities, from broad character-based comedy to troubling moral inversions and outright nightmares. Arakawa strikes me as an intelligent writer. Fullmetal Alchemist is very good and this is more of it, so that made this pretty much a no-brainer as far as I'm concerned. I'm a completist that way.