Yasuke

It has quite good production value, at least comparable to Castlevania or DOTA: animation, art style, sound, music. If only the children were not shrunk adults and had proper proportions.

But my main "complaint" is the story. No, it's not particularly bad. Considering how (extremely) fast-paced it was, it's ok. But it has no world-building and no character-building despite having quite interesting characters. And it has a lot of... Unrealized potential.

If I was doing it I'd do it Berserker style. You see, Yasuke was in a very interesting position: he was a very rare sight of black man in Japan in general, let alone among samurai. I would depict his story from becoming a slave to coming to Japan and becoming samurai. If done correctly, this would also have a historic value.

I would not show anything supernatural despite, maybe, some slight hints during this time. Definitely no robots, which make no sense (as well as Russian werebear). But since Nobunaga's death and Yasuke's short stay with Nobutaka are poorly depicted... That would be a way for supernatural to come into the story. Have something horrible happen, make Yasuke get depressed as result of this (and his master's death), so that he retreats and starts drinking for several years.

Then the initial happenings of the anime, through which he encounters the girl, who happens to be part of that supernatural he tried to escape. Despite her mother's death he tries to retain his honor and fulfill her request alone. They slowly travel, getting to know each other and the "rules" of the supernatural, meeting the "Doctor" and the so on.

But this needs to be much slower in order to properly build characters and the world. Definitely not 6 episodes. Maybe 24 or so, with 13th episode serving as transition between 2 parts.