So here's the problem with Gundam 0083, all of that stuff is completely de-emphasized.
At the end of the OVA Nina Purpleton betrays the Earth Federation shoots at Kou to be with Gato and Zeon, Nina is shown leaving with the Zeon, Gato sacrifices himself to allow the Zeon to escape, Kou whines like a baby, and then you get a brief montage of the Titans forming, along with most of the main cast joining them and then apparently Nina defected from the Zeon back to the Earth Federation despite being an accomplice to genocide, and apparently Kou is too big of a loser to join the Titans and for some reason Nina Purpleton was not only not executed but allowed back on an Earth Federation base. The OVA then ends with Nina and Kou making faces at each other.
If the OVA was about Nina having complicated feelings for Gato than that needs to be shown with more than a few goofy faces in the last 30 seconds. If you want me not to hate Nina than have her do something to redeem herself. If the OVA wanted to emphasize that Nina cares about the person Gato used to be, than emphasize that instead of having her leave to be with the Zeon after they already started to drop a colony onto the Earth. It instead just looks like Nina didnt care about the millions who died, and instead went right back to the Earth Federation because her boyfriend died. Nina comes off like an incredibly shallow human being who will join anyone's side as long as she finds someone hot.
Why did Nina leave to go with the Zeon at the end? Why did she go back to the Earth Federation? Who knows because all of that stuff happens at the very end of the OVA
The basic idea of Nina loved Gato. but then Gato broke it up because war started, and then when Nina sees Gato again his become a hardcore Gihren Zabi loyalist, and she has to come to grips with the changes in Gato is an interesting idea but instead it just inserted to create a bunch of drama about Kou Uraki's girlfriend leaving him for another man, and then her coming back because that other man is dead. Nina comes off as incredibly shallow, and Kou Uraki comes off like a complete loser for taking her back.