This really small mini series is an original net animation was produced by Gainax in association with Subaru. Even though it is really short, but also recent, it also has the possibility of gaining a TV/manga adaptation if it get popular enough. Personally I think it has a really low rating due to its length, but I'm going to review it based on what the series offered out of its 20-minute running.
**May contain spoilers, harsh language, or graphic images**
Story (7/10): What was offered by these 5-minute episodes was a main character, Subaru, with a preview to a past event, who "magically" happened to stumble across her school friends turned magical girl by an alien life form called a Pleiad (which makes sense because of the art throughout the animation). But before that she found a strange room in her school with an even stranger person inside, which she meets at a later point. So on her first magical "mission" with the group we find out that their objective is to collect these shooting stars using a sealing technique (apparantly made easier with more people). But wait, there's more! Wouldn't you know that the person she had met in that strange room, Minato, is actually their rival trying to collect the star fragments for his own purpose! But don't worry, since during the climax Subaru learns that he had been affected by that meteor shower that Subaru had witnessed when she was younger (past event), and had apparently gained some power out of as well. However I find it confusing why/how Subaru seemed to love Minato, as seen in at least three scenes: (1) when she tries to enter the strange room and can't, she then cries; (2) when she flies toward him and hugs the "evil" out of him, plus their departing words; and (3) when she visits the strange room after the climax and finds a blooming flower in her presence. If they're going to throw a romantic subplot in the series, make it flow with the rest of it at least (but I'm sure they did their best given the time restrictions).
Animation (7.5/10): Really good background art, character designs, and very good fighting scenes.
Sound (7/10): No OP, but a somewhat full-length ED with a sensible song. All the characters' voices where fine (as in not annoying high-pitch girls) and the sound effects up to par.
Characters (7/10): Having really not much to go on in regards to character development, I can only give the series so much. If this were to get a TV/manga adaptation, it should definitely keep the romantic subplot (shown to go great in Sailor Moon and exception well in CC Sakura, causing a whole other series to diverge from just that). Revealing the other magical girls' pasts is a must as well.
Overall (7.125/10): Although the main character Subaru was just litterally pushed into this magical girl scenario, giving the series an obvious "rushed" feel, it was definitely a nice way to pass 20 minutes. If this comes out in the future as a full-fledge series, I'll definitely give it a shot, since I don't like most magical girl series. To be honest I absolutely loved Madoka (the only reason I watched it was due to the large influx of images on wallpaper/image sites I live on - 4walled, konachan, imouto, danbooru - so I decided to give it a try) and when I saw this image, I decided to give Houkago no Pleiades a try.
Personal Nostagic Value
EDIT(6/24): Redone scores