Cliché Storm: As noted on the main page, VO is packed with elements similar to or straight-up lifted from other series. Whether this contributes to or detracts from the show's enjoyability is entirely up to the viewer
Fridge Logic: In the final two episodes, we learn that the crow never intended to give humanity a fair chance and plans to destroy the earth anyway and then betray its masters. To do this, it absorbs Rei's remaining four arrows to gain enormous power. So... if this was its plan all along, why didn't it just eat all of Rei's arrows at the very start of the series? If four arrows made it practically unto a god, ten arrows would have likely made it unstoppable even for a full Vivid team, and at best only VividBlue would have been around to oppose it.
Hilarious in Hindsight: Rei, being not only an expy of Homura, but an antagonist for a good chunk of the series becomes funnier when you take into account that Homura became an antagonist herself a couple of years later.
Episode 6 has such things as Himawari and Akane touching each other and Wakaba scooping up Himawari in a Bridal Carry.
Wakaba and Himawari continue to act like a couple throughout the series, often holding hands and spending a lot of time alone together.
Episode 8 gives us little gems like Wakaba hugging Himawari while the girls see Akane before she's rushed to the emergency room, and the two of them wearing matching green and yellow clothes.
Episode 9 takes the Himawari x Wakaba ship to a whole new level. It starts off with Wakaba cleaning Himawari's apartment like a housewife. Then she makes her go out with her in a cute dress. The barettes that Wakaba gave to Himawari turn out to be her most treasured possessions. Then the ending tops the entire episode with Himawari setting up every Sunday for the next year to be spent with Wakaba.
Nausea Fuel: All that mayonnaise...Akane slathers it on everything she eats...absolutely everything...and then she makes the other girls try it...and they see no problem with it, and all of them...all of them actually enjoy the stuff...oh God. Akane please stop...Akane NO!
And then in episode 10, it exploded and it was absolutely everywhere...all over the room!
Nightmare Fuel: The crow SWALLOWING REI WHOLE might count for this, due to how it comes straight out of nowhere.
Tear Jerker: Rei talking with Akane about how she wants and needs to be friends with her and the other Vivid girls, while simultaneously thinking about how she wants to kill them, without realizing that they're the same people.
What an Idiot: Kenjiro making the entire docking system dependent on Akane. When Akane is put in the hospital, the other girls have no way of forming any of the Vivid forms, and they nearly lose a battle as a result. It's implied that there's some sort of reason that the system is designed this way, but it's never properly acknowledged or explained.