Wings of Rean starts off fairly promising. It's got all the ingredients for an interesting clash of beliefs: military vs. political, peaceful vs. warmongering, etc, and the exploration of how two worlds could meet. Unfortunately, the story is so confusing and nonsensical, that it is fairly impossible to discern what the heck is going on. Who're the good guys, and who're the bad guys ought to be fairly straightforward, yet the OVA can't be bothered to make the distinction.
It's hard to tell what any of the characters' motivations are and why they're there. There is almost no character development, and the little there is, is not dramatized well. It's hard to tell who is supposed to have the change of heart, and for what purpose. It's clear that the animators were going for an anti-military, pro-peace sort of message, but it comes off as showing the American military as being power-hungry ignorant bigots, which in this day and age, is insulting (accurate or not).
The animation and sound are decent, but nothing particularily outstanding or notable, but not in an okay way. It really could have done more, for instance, have the two worlds be colored differently, or something, but again, it's like the OVA couldn't be bothered.
Overall, I would give this OVA a miss. There's really nothing to tie the viewer to the characters, and there isn't a whole lot of action that's fun to watch (mostly because you're trying to figure out what's going on). The characters are cardboard, and the art is blase. Find something else to waste your time.