I like it- very cool sub. That camera angle made me tilt my head way to the left at first :). However, please don't take this harshly as it isn't intended that way at all, I'm not quite getting the underwater feel to it. I think it's because the sub is seen too clearly- or maybe the lack of bubbles. I don't know. The background buildings seem like they're underwater though.

I really like the lines of your sub. I think you probably make great spaceships too.