People are generally more interested in action type anime with a male mc on their front cover. So when you have a series like this, with 2 really young looking girls with a synopsis that doesn't seem to have any deep plot, it gets overlooked very easily.
However, Koukaku no Pandora is a show that manage to combine its yuri elements into a comedy that makes you want to watch more of. I immediately liked Nene and Clarion when I saw them. This show also have a good mixture of its insane randomness and random comedy moments in the background that makes it so enjoyable to watch.
Definitely would recommend to give this series a try!
