This show has no meaningful plot and is solely built on the idea of using fan service to push the story forward. With characters having minimal backstory with almost no compelling information revealed about them, the only role literally becomes creating these weirdly aggressive make-out scenes that are dripping with shallow sexual tension; there is practically nothing to make these characters memorable, or worth investing any kind of emotion in.
The art is fine, but wasted on scenes of soft-core porn, and the backgrounds are dull in most situations, so even if the battle scenes have some decent to mediocre choreography, it is made irrelevant by the waste of artistic abilities elsewhere.
Overall, Valkyrie Drive: Mermaid feels like a poorly mutilated love-child of Sekirei and Soul Eater.
