Ryuu Seiki

Alright, My review is going to be very biased, as the first episode could be taken on its own, and could very well stay that way on your list without losing much.

Story:
The story is unique, something I haven't seen before in monster shows, or science fantasy or science fiction. Suddenly, a string of violent deaths occur, and dragons are discovered on earth. This is where it gets interesting, as dragons neither seem to be able to breathe fire or do magic, or any of that, which I very much like. It turns out that things like guns are effective, and we are fully capable ... of hurting them.

A girl, probably in high school, begins caring for a dragon, beginning to raise it under the impression she can work beside him to take out her angst against the world. Grey and edgy, but with touching moments. It has a nice emotional range, and I hold the first episode close to my heart.

the second episode? ever watch dune? it'll remind you of that, with some Rocky and a dash of Eragon. it's a 180 degree shift in tone. it still has decent story and sci-fi elements, but with a post-apocalyptic theme.

Technical, art, sound, etc:
Sound design is amazing for its time. ever hear someone trying to stab an office window with a fork, then drag it along the glass? you will, and you'll cringe. simply stunning for what it was. I'm not biased on a medium's age though, and have to give it a very good rating. music was great, but some room tone couldn't hurt. the art, on the other hand, is amazing. many scenes could be paused and put on a wall as a painting, and the characters are well rendered and thought out. A sunset washes the colors in reds, pinks, and yellows, and SHADING IS NEVER SKIPPED ON ANYTHING. seriously, today's animes do that a lot. not too much panning, and shots with less animation don't stay too long. it holds up against today's stuff well.

Characters:
Characters are a solid part of this show, enough to say telling you what they're like could be a spoiler, so I'll leave what's above, and that this show doesn't idealize anything. The characters feel they have depth, and you aren't given their life stories, and their past clearly has an influence on them. outstanding characters.

overall? 8/10, underrepresented, and wish each episode was a 24-52 episode series. it didn't have enough time, but definitely was set up to be anywhere between Death Note, Shingeki no Bahamut, and Grave of the Fireflies, and I want a remake that goes to all those places!
(but never made good on them, so that wasn't spoilers)

I've seen far more worse and better anime OVAs in the 26 years that I've watched anime. Dragon century is for me quite in the middle and since this was like other OVAs a one-shot title it was '' bearable" but as well it seemed a bit unclear if you don't watch it several times to get it. First of all part 1: 1990 AD, I was surprised by the violent content and would have LOVED IT if I was like 12 years old or something :).
Clearly there you can see how the human dominion comes to a crash course once dragons appear ... with very bloody consequences (don't be a bitch by the amount of blood if you can't stomach it) and a girl gets involved by saving a dragon egg that hatched.
But as the story progresses there is a meaning to the dragons appearance when a demon god fucks up the human world and needs to be stopped and in some way the girl and dragon do it, leaving some destroyed buildings around, and a timerift opens so dragons can enter the human world.
Part 2 on the other hand, you will be confused the 1st time because it starts in a new era named R.C 272 ( Ryuu Seiki translated to Dragon Century) .
It appears that the human world is changed in to a human/dragonworld where
dragons that lives far longer than humans are used as pets, fighting in arenas for fame.
The young hatched dragon from part 1 is now a few hundreds of years old and encounters a young girl that possibly is a grandchild in the future related to the girl in part 1, and for some reason the demon has be revived or whatsoever which is time for the dragons to stop and save their world, and it felt unfinished.
The animation was 'respectable for its time', it was cheap but not THAT cheap, but hey what do you expect from one-shot 2 part ova.
The characters themselves were quite good, I had hoped that a bit more attention was given to the dragons since they are the main part of the story, but I had no problems with the female character, she had an undaunted, non airheaded, strong believing and understandable personality that drops heavily in part 2. Part 2 had more dragon characters and human characters but was all about it.
It was enjoyable on the basis that it's just a short popcorn OVA and was good to me but could have brought soo much more potential on the goddamn table, but after so long it is forgiven. So yeah in the end its up to you to make a opinion.

"Ryuu Seiki" has decent art, but the rest of the technical aspects, including animation and sound, feel flimsy. The characters are difficult to sympathize with and have contrived backstories and abilities. The plots for both episodes, which rely on these contrived backstories and abilities to progress, don't make much sense. Also, since this OVA is just two 30-minute episodes, which each tell separate stories that are only loosely tied together, events happen so quickly that it is difficult to comprehend what is going on at times. It ends on a cliched note.

There are worse OVAs out there, but this one is not particularly good; it's ... mediocre at best.