11eyes could have been a not so bad anime if the plot was executed correctly. While it wasn't the most original, the premise wasn't half-bad either. Instead we get 12 episodes of pointless fan service, mediocre character development and massive plot holes.
Story:
It was actually hard to find a story within the first half of the show. In fact, it was nothing else than bunch of kids fighting the black knight for whatever reason. You didn't know why they were transported there and why the black knights were trying to kill them. Until you get to second half, it went down hill. I could complain that the first half was confusing me more than ever since the story wasn't developing, but after the second half it was actually better to tell nothing at all. What lacks in the story is the fact that 11eyes made so many plot twists and not intelligent ones that it became embarrassing. A 12 years old could make a more interesting story than that. In the end, the story left many holes and the viewer is still as much confused, or even more, than he was at the first episode.
Art/Animation:
The art was fair to be honest. While most the characters lacked the ability to dress as something else than their school suit, they were actually distinctive. Not the best, but certainly not the worst.
The animation on the other end, was bad. What strikes me the most, is the terrible fighting choreography.While some expressions the made were plain dumb, they were at least walking correctly.
Sound:
It is very sad when the sound is actually the only point that is decent for a show. No doubt about it, the opening and the ending theme song was enjoyable. There's just a few annoying voice acting, most notably the girls cast, but the viewer can easily get over it.
Character:
Where do I begin? Beside the fact that they were mostly cardboards, retards and that the protagonist is lame, there's nothing more to say. The characters were fair at the beginning of the show. While there are few complaints, they were at least interesting. Somehow, the producer thought it would have been a good idea to add a bit(or too much) dementia in the character development. This is where everything gets embarrassing and everything goes down hill. What I hate the most is that you can't say which is more retard between Yuka and Kakeru. Yuka is a lame yandere and a dumb blonde(even is she's not blonde) and Kakeru is just lame, retard and ignorant. The three other main characters aren't better either. Yukiko is just plainly annoying, Misuzu is a slut with no soul and Takahisa is your typical hot head guy. It is funny to see a stereotyped cast, but it's even funnier to see a stereotype cast trying to act in drama situations. I find it very very very sad the best characters were actually the ones that were just there for fillers. Yes I'm talking about Saiko.
I did not enjoy this show, while it wasn't that painful, the story didn't make any sense and the characters are quite lame. Not to mention that they actually inserted fan service in scenes where it was supposed to be sad, or at least emotional. 11eyes is badly executed and is perhaps among the worst anime of 2009.