1.- The story: If you read what it is about like (an anime where some quintuplets study with a guy) doesn't sound that interesting, but if you watch it like fr it gets you very hooked since the beginning. Like to know how does Fuutarou manages to get those girls to study is a great way to start the anime. and the way it develops is really great too.
2.- Art: Well, the art basically is really good, i liked how they are drawn but in some way the drawings and the details are a bit exagerated. (You know what im talking about) but out of that kinda exagerated or so, the art is really great, the movements seem to be smooth and is pleasant to see.
3.- Characters: Charachters have many ways of been rated for example the way they are designed. About that, i guess the quintuplets have a very unique design and if you inspect it more carefully, all of its design(from the face to the clothes and accessories) are all very related to ther personality and it seems to be more congruent to the story. Other way is the character developing. In that way there were some things that weren't explained at all, but those parts make the watcher be more involved in the story trying to find some things out and that also hooks a bit. So that "disadvantage" turns to be not that bad.
To sum up this was a very enjoyable anime which I fully recommend, and trust me it will be worth it.
