I really like Japanese anime and I have come to expect good animation and deeply interesting stories, mixed with some Asian quirks. Harlock has almost none of that. The animation is 3D and even if pretty well done, in the end it is kind of repetitive and lazy. The story is a complete mess, combining classic pirate ideas with space opera kind of battles, only in - again - such a lazy way that it totally annoyed me.
Let me give you a taste: there is a space ship that is kind of indestructible and has an immortal captain. It battles the horrible manipulators of the human race which hold the Earth hostage as a possible reward for the faithful, who would be allowed to return. And they have a zillion ships and planet buster weapons, but this pirate captain faces them head on and wins, because... he has an indestructible ship. Every character in there is a bumbling idiot, switching allegiances and going 180 on every decision they made, until you don't get anymore what the movie is about and what the characters are fighting for.
Bottom line: a waste of time with nothing to teach except... flowers are pretty, I guess.