"Gonna be the twintails!" is a show created by otakus, for otakus, that makes fun of otakus.
From the get-go, it revolves around an invasion of otaku aliens from another planet who feed off the positive energy humans give through their love. Essentially they are a bunch of perverted losers who leech off of others and ruin people's lives, sound familiar?
Our heroes, a group of twintailed heroines must use their love of twintails to fuel their magical girl powers in order to defeat these monsters, thus saving the human race. Along the way, it's a hilarious journey with perverted humor, (Like gender bending, tentacles and ecchi scenes) and then just about anything else that you will see in a typical high school comedy anime.
The aliens are COMPLETELY hilarious, the cast is great (Especially Twoearle), and pretty much everyone in the show is necessary, you don't have 50 different characters that are completely irrelevant popping up for 30 seconds just to fill screen time. The voice acting is solid, the theme song is catchy ("LES-CUE!"), and I have no real qualms about the sound. Likewise, the artwork is great and pretty typical of a modern show. (The boobs are exaggerated as hell on tail yellow for comedic effect)
My only qualm with this show was the fact that the story, like any magical girl show bar madoka, was the sheer predictability. While it was entertaining as hell, and did a great job of satirizing anime similar to something like gintama, like gintama the story is kind of lacking, since the point of the show isn't the plot.
While it may not be quite a masterpiece, it's an absolute blast to watch, and I highly recommend it if you're into this sort of show. Anyway, there's two types of people who rate this show poorly, people who either-
A: Don't like this kind of humor.
B: Just don't get the satire.
If you don't enjoy perverted jokes and constant porn references, like Sekotai Yakuindomo, this is not your show. This is a show created to mock the present state of anime, especially the magical girl genre, and it heavily exaggerates perverted scenes in order to make a point. Try not to take this show too seriously.