This bite-sized horror story offered nothing new to the table, but proved a fun distraction. Sadly, any fan of the horror genre will be able to guess where the whole this ends up about halfway through, but given the quick pacing, that in and of itself doesn't ruin the outing.
The mangaka's attempt to marry the innocent visuals of the mermaids (all cast as girls in school swimsuits) with the horrific behavior of the characters only succeeds halfway. The impressive images of gaggles of girls swimming through the air and between the walls of the class rooms certainly adds an other-worldliness to the work, but I felt that the actual horrific visuals came up sorely lacking. That said, the manga did put a slightly refreshing spin on an old theme.
If you're a fan of horror and a fast reader, this one is worth the 20 minutes it will take you to read it.
As a very short horror story, I've read better. The twist on the plotline is predictable but as those things you are happy to see you're completely right.
The author tries to create an environment where the real monsters are the girls, as the mermaids, really don't try to kill them but fails miserably with the lack of elements that make the girls scary or the murdering repulsing.
Really this story is only good if you don't have anything better to do.