Vividred Operation: D+
This is official art, by the way
So this series is ostensibly kind of about techno-magical girls, but in truth is really about underaged girl's asses. And to a lesser extent their breasts.
So there are these girls and for reasons which aren't entirely well explained they wind up wearing jet suits and fighting invading aliens. The Jet suits are powered by this cool new reactor that we built that runs on extradimensional magic. Why we didn't give the jet suits to trained military professionals isn't well explained but probably is due to one of the girls' grandfather, who would be creepier if he didn't get brain-swapped with a stuffed animal in the first episode. Naturally there's hijinks as the full team of four gets together and the mysterious girl who appears to be working with the aliens, and starts out cold and not wanting to be friends but warms up eventually because she's lonely and the main characters are the only ones who have ever tried just being friends with her.
All that's pretty formulaic, but I am not going to say that something that is formulaic is inherently bad. It can be well-executed, and the fact is that I do kind of like several of the characters and the execution in places. The show has enjoyable moments and is fun to watch and listen to, but it's flat. There is no spark, no risks taken. No great lessons learned, no moving moments of understanding or betrayal. Even that would still earn it the C, that were all I had to say.
What ruins it for me, and rarely will I say this, is the fan service. Now, I want to go on record with saying that I enjoy the lovingly animated female form as much as the next creepy nerd on the internet. Fan service is not inherently bad for me, and can be used to enhance storytelling while ALSO providing titillating content for viewers. To this end, I categorize fan service occurs into three varieties:
1) Integrated Fan Service. This is the fan service where we're shown cleavage, jiggling boobs or panty shots for a good reason within the story. Often it's because it's what a male character present in the scene is focusing on, and it's shown to help us sympathize with his horniness, and the awkwardness that ensues from that. It might be deliberately sexual to showcase a character's depravity or innocence, based on their reaction. It's also meant to titillate, but it serves a significant purpose: the fan service is fully integrated and justified by the story and setting. Bakemonogatari and Haganai are full of this, and Speed Grapher had its fair share as well.
2) Tongue-in-Cheek Fan Service. These are the humorous panty shots, the fourth-wall breaking moments where other characters block the camera, or where circumstances contrive to cause the characters to get into situations that result in clothing being lost or undergarments being shown off far too often for it to be taken seriously. Koihime Musou is full of this, as is Dog Days. The fan service is not integrated into the story necessarily, and probably could be left out, but it is given a nod from the characters themselves, and so is contextualized, usually as humorous.
3) Straight-faced Fan Service. In this form, we get acontextual shots that showcase a character's body purely for the sake of titillation. Its use has no impact on the story, and nothing to do with any character's portrayal or perception of others, and nobody in the story seems to notice or care, much less comment. It often seems as though the cameraman just happens to be putting himself somewhere where we get a shot of a girl's magnificent ass, or rack, or whatever. This type is present only for the audience's benefit. The lack of integration causes mood whiplash, desensitization to further uses of it and an overall weakening of the audience's ability to engage with the story.
Type 3 is the kind in Vividred, and it's the kind that offends me. It marks a story as being weak, because if you feel the need to have lovingly animated ass jiggle for no reason other than to show it off, it makes me as a viewer feel like that's all the show has to offer. And that's why Vividred is probably not worth your time: because pretty much all it has to offer is several barely-teenage girls' butts in short shorts; nothing original or creative, or even particularly noteworthy.