The first reason I pick up this is because of the author. Ogawa Maiko previously worked on the illustration of Toaru Hikuushi e no Tsuioku (also translated as The Princess and The Pilot) and I love the nuance shown in her drawing, especially expression of the main heroine.
In short, this is the story about a boy and an alien girl on path of conquering earth.
The story is cue in a way, but also slow. From my own description, it has that feeling of dusk or twilight (the time of the day, not the novel), a relaxed, slow but sure pace instead of the all too rushed shonen action or the trying to hard to be dark and serious kind.