This 4 OVA´s are nothing but the best. Even now, when I think about it, I still don´t know how the managed to produce a story so complex with only 4 episodes. Its very original, it takes place in some apocalyptic future were humans fight sea humanoid hybrids created by some sort of crazy ecological minded scientist that wants to wipe out humanity and replace it for his creations by rising the sea level. The story centers around Tetsu Hayami, a very skilled marine with some kind of rude nature, and the young recruit Mayumi Kino, and how both of them get involved into the climax of this global scale war.
As pros I would say:
1.- The plot is fast, entertaining and solid. It has a huge complexity and is amazing the amount of detail in each episode but on the other hand you never get overwhelmed by its well written story.
2.- It has a really good graphic style that mixes 3d with traditional animation, in my opinion, perfectly, with beautiful colors that enhance the deep sea atmosphere and a clean stroke that looks really neat.
3.- This atmosphere it manages to produce, makes you feel like if you where inside the very own submarine.
4.- It has lots of action in it, even with so many things to explain it has many action scenes that entertain a lot.
5.-The message beneath the series is really deep and I personally love when any anime I watch leaves me thinking and questioning things I never thought I would.
As cons I have to say:
1.- I hated the fact that it was so short, but you know what they say, good stuff comes in small suits.
Resuming, If you look for something new with an amazing story this is a choice you wont regret, that´s why I rate Blue Submarine N°6 with 5 stars out of 5.