Japanese Cartoon companies like to do this a lot. They strike gold with a TV series and decide to follow it up with a high-budget OVA or movie for the masses to eat up hoping to squeeze a few more yen out of the pockets of the sheep-like Otaku masses. Even though there's a pattern that almost always repeats itself, these projects rarely ever fail to stir up a good amount of anticipation.
These productions are hardly ever handled properly and almost universally disappointing. Sometimes the writers and directors have forgotten what made their original productions worthy of a spin-off in the first place and other times completely new teams come in and miss the point entirely. The biggest reasons for this failure, in my eyes however, is that they almost always try to cram way more story into the production than the alotted time will allow or they don't try to put nearly enough in and you get left with nothing but either a rushed along and barely thought out mess or a pile of shit fanservice. Mai-Otome Zwei kinda rides a fine balance between the two.
Mai-Otome Zwei picks up the story one year after the events of the TV series. Our cute little Arika has blossomed into a full-blown Otome with the astonishing magical powers granted to her by the Blue Sky Sapphire and Mashiro is well on the road to becoming a respectable Queen, but is still a bit overwhelmed by the responsibilities of the title.
The series opens with a group of Otomes on a mission to stop a giant meteor from crashing into the planet followed by Garderobe Academy being attacked by a mysterious (though very familiar-looking) shadowy figure capable of turning any Otome encountered to stone by petrifying the nanomachines inside their bodies. And then, shortly after that, Mashiro goes missing and Arika sets out to go looking for her. It's a fairly simple story really, as the show's only four episodes long.
I do applaud the writers for keeping it simple. As I mentioned, these OVA spin-off shows tend to try and cram way more in than they can possibly cover and end up shitty because of it. With a runtime of four episodes, Mai-Otome Zwei's problem is that there's not enough story to fill out the time permitted, so they had to fluff it up quite a bit.
There's a healthy amount of fanservice this time around with nearly 1.5 episodes completely wasted on it. The second episode of the series honestly shouldn't even exist, because it's only there for comedic purposes and it's really not even funny. Coming off the first episode, which had a fairly serious tone throughout, the second episode feels incredibly tacky and is a monstrous waste of time. The first half of the third episode is fairly throw-away as well. It's one of those bath scenes to get as many Otomes naked as possible and groping around on each other. Not that the characters aren't attractive or anything and hardcore yuri fans might enjoy it, but again, being slapped into the middle of a story where Otomes are essentially dying, the Queen's missing, and the planet's future is in jeopardy, it seriously doesn't fit in at all.
When it's staying on point, Mai-Otome Zwei's story, though obviously lacking the depth of the TV series, can be fairly enjoyable. It's fast-paced and there's a lot of good drama and action that balance one another out. Spending more time with a cast of characters that was enjoyable to begin with is definitely a plus as well. I feel that this story could have worked better as one of those short 60-75-minute movies with the fanservicey/comedy bits thrown out, rather than stretching it across four episodes that were released individually three months apart. The quality is definitely there and the story's self-contained enough to work, but I suppose they had to milk the poor otaku somehow, though.
Being that it's an OVA, it should be quite obvious that they pulled out all the stops when it came to the show's overall presentation. Mai-Otome Zwei has all of the fireworks and zazz that were missing from the TV series, so while the story may fall a bit flat, at least it's damn pretty to look at. Character designs are still just as good as they were before, but the animation is where they truly shine, especially in the many action sequences throughout the show. Zwei is high on action and the battles that take place are far more exciting and entertaining than what the TV series offered. The action can be just as intense and captivating as it was in HiME and since there's a good bit of it, your eyes are sure to be pleased. Additionally, the artwork is a lot more consistent and detailed, with characters' looks not suddenly turning to DERP and backgrounds that actually manage to call attention to themselves.
Much like the original series, Zwei's music doesn't really end up calling much attention to itself. Even though it's a step up from the TV series' soundtrack, it's still fairly generic by comparison to most other shows. It's there to sit in the background while the pretty pictures do their thing. The insert and closing themes are decent if you're into that kinda thing, but I found myself skipping through them.
Huh... I guess this ended up fairly short compared to the walls of text I normally write about Japanese Cartoons. Fact of the matter is that there's really not a whole hell of a lot to say about it. It's a show that comes in, wows you with some pretty pictures, and leaves.
My-Otome Zwei is damn-near dry when it comes to substance, but makes up for it by packing in a lot of the style that was sorely missing from the TV series. If anything, I'd say it's more like a magical-girl attempt at being a Rambo movie. A lot of flash and not much else. It's a cash-in, plain and simple. It's more Otome, but with the TV series, I'd honestly had my fill and didn't feel the story needed to go on any longer. Odds are, if you enjoyed the original TV series, you'll find something to like here. For me, however, beyond the pretty fight scenes there really wasn't a whole hell of a lot to take from it.
Japanese Cartoon companies like to do this a lot. They strike gold with a TV series and decide to follow it up with a high-budget OVA or movie for the masses to eat up hoping to squeeze a few more yen out of the pockets of the sheep-like Otaku masses. Even though there's a pattern that almost always repeats itself, these projects rarely ever fail to stir up a good amount of anticipation.
Mai-Otome Zwei picks up the story one year after the events of the TV series. Our cute little Arika has blossomed into a full-blown Otome with the astonishing magical powers granted to her by the Blue Sky Sapphire and Mashiro is well on the road to becoming a respectable Queen, but is still a bit overwhelmed by the responsibilities of the title.
I do applaud the writers for keeping it simple. As I mentioned, these OVA spin-off shows tend to try and cram way more in than they can possibly cover and end up shitty because of it. With a runtime of four episodes, Mai-Otome Zwei's problem is that there's not enough story to fill out the time permitted, so they had to fluff it up quite a bit. 
When it's staying on point, Mai-Otome Zwei's story, though obviously lacking the depth of the TV series, can be fairly enjoyable. It's fast-paced and there's a lot of good drama and action that balance one another out. Spending more time with a cast of characters that was enjoyable to begin with is definitely a plus as well. I feel that this story could have worked better as one of those short 60-75-minute movies with the fanservicey/comedy bits thrown out, rather than stretching it across four episodes that were released individually three months apart. The quality is definitely there and the story's self-contained enough to work, but I suppose they had to milk the poor otaku somehow, though. 
Being that it's an OVA, it should be quite obvious that they pulled out all the stops when it came to the show's overall presentation. Mai-Otome Zwei has all of the fireworks and zazz that were missing from the TV series, so while the story may fall a bit flat, at least it's damn pretty to look at. Character designs are still just as good as they were before, but the animation is where they truly shine, especially in the many action sequences throughout the show. Zwei is high on action and the battles that take place are far more exciting and entertaining than what the TV series offered. The action can be just as intense and captivating as it was in HiME and since there's a good bit of it, your eyes are sure to be pleased. Additionally, the artwork is a lot more consistent and detailed, with characters' looks not suddenly turning to DERP and backgrounds that actually manage to call attention to themselves.
Much like the original series, Zwei's music doesn't really end up calling much attention to itself. Even though it's a step up from the TV series' soundtrack, it's still fairly generic by comparison to most other shows. It's there to sit in the background while the pretty pictures do their thing. The insert and closing themes are decent if you're into that kinda thing, but I found myself skipping through them.