For a start, let me say I appreciate that this is an adaptation from a generally highly-regarded manga by none other than Lynn Okamoto, however the series needs to be taken at face value rather than drowning it in seas of fans who won't dislike anything about it regardless of its flaws.
Story - 6/10.
At first, I probably would have given the story a higher mark - it began well, dark and interesting and it honestly looked promising. We start off being introduced to Murakami with views into his past, then we meet Kuroneko. However after the first few (four, I think) episodes, the cast starts to grow, and so the story declines - dark, mysterious or gory scenes were juxtaposed with fanservice and gags, poor attempts at comedy that really did not fit into the atmosphere they tried to create in the episodes. What could have been an interesting sci-fi drama becomes a show trying too hard to please its fanbase, with random sections within almost every episode becoming pure fanservice nonsense. And towards the end there is a LOT of deus ex machina, not subtle at all and which will make you think, "wha? how did that even happen?". If a more realistic pattern had been followed Murakami would have been dead long before the latter third of the series. The story is just trying too hard, introducing too many twists and turns, different genres and different ideas - it's shoved in your face like "here, have loads of stuff, this is making this really interesting and deep right?!", which it doesn't. It doesn't know where it wants to go or what it wants to be but still manages to act pretentious about it, it is confused and comes across as really artificial as the story has no flow to it. And I won't say much about the ending except it was heavily anticlimactic and weird, I was left thinking "huh? is that the end? what is happening I don't understand".
Art - 6/10.
Little more than average. A very generic anime style now, done in a "meh, that looks okay I suppose, it's not awful..." way. I felt the palette was not very expressive especially when taking into account the dark scenes put next to the comedic/gag/fanservice scenes, the transition will leave you reeling. Character designs were pretty generic, you have the pink haired one, the blonde one, the dark mysterious one, the big-boobed shy one...all of the characters had defining features but sadly that was mostly the colour of their hair. Special effects were not special, in fact they were pretty cookie cutter and uninventive, which baffled me. They had loads of girls with loads of different powers, and they couldn't make it look cooler than it did.
Sound - 7/10.
The first OP of Brynhildr was okay, although it can't actually be classed as "music", it was punchy and it had a good beat and set you up for the episode and the sci-fi feel of it. However the second OP I skipped as it went from a pleasant alien-ish sounding dubstep track to a screamo hardcore track I just couldn't bear. It completely shattered any mood whatsoever (which I think is pretty important for the OP to do) and I guess it was to try and make it seem more epic? No idea...The sound in general was okay I guess, as usual I didn't really notice any of the actual background music or effects, but I didn't notice anything hugely out of place. The character voices were okay too, I wish they had made Kana have a more believable machine-voice instead of the "moe" voice she was given, Kotori's voice was kind of predictable given her "the shy one with big boobs" status, Kazumi's voice was actually good to listen to - although I did not like her character generally, she had a more unique voice. Kuroneko's voice was kind of generic too. The seiyuu did a decent job but I just don't think the material gave them much to work with.
Character - 6/10.
I can't give character more than a 6 (and was considering lowering my mark, however...). Let me start by listing a few stereotypes here - the Gary Stu, the unmemorable "every guy" guy who, for no real good reason, takes on caring for a harem of dangerous girls and trying to save them because he's just that nice. Oh and he had a tragic past or something so he wants to save everyone. Despite discarding even a scrap of realism for his character they still attempt to make us care about him and his motives. *facepalm* The childhood love interest, who has the Mysterious Amnesia. The shy, big-boobed one who can barely form a sentence. The perverted one. And the mysterious antagonist doing bad things to poor innocent girls for his own weird motive. That covers pretty much every main character in the series, except Kana, who doesn't really fit into much of a stereotype, I guess she's the overly fragile one who thinks people are trying to take advantage of her all the time.
Anyway, I digress. There's really no depth to the characters at all. Poor Murakami suffers from Incredible Lack of Realism disease, which means he is almost impossible to relate to - we are given a rushed "explanation" as to why he wants to save all the things, however as I previously stated introducing every character type ever to the story and his harem was totally at the expense of any actual depth and realism in the characters. I found that even as characters died, I just sat looking at the screen thinking "meh, that's sad, I should care about this but I can't" because there is absolutely NO realism or real story telling behind them. We get "here, have some characters", and a manipulative plot which tries to make you care about them (for example Kotori's suicidal thoughts, which then mysteriously disappear.)
Enjoyment - 6/10
Although the series took a serious nosedive about a third of the way through and became almost unwatchable during the last third, it was an okay watch if you don't expect much. I essentially muscled my way through it (which was hard, believe me) without wanting to actually watch any more of this confused mess within the last 4/5 episodes, however previous to this it was an ok watch, flaws are obvious but before the major asspulls begin it presents some decent episodes (namely the first 3/4).
I can't really say I'd recommend this anime unless you KNOW what you're getting into, you know that it's a mediocre adaptation of Lynn Okamoto manga and that you know it will go downhill soon after the first third.
If you want something with an interesting premise then by all means watch it just don't expect this show to deal with any actual issues, show any real depth or conclusion, the only thing which kept me going sometimes was the mystery shrouding the girls and the simple "I don't really care, but WILL HE SAVE THESE GIRLS?!" feeling, more of a curiosity than anything. That and wondering how much worse they could make it.
So yeah. Don't expect much/anything in terms of realism or storytelling from this anime and you might be able to tolerate it somewhat.
