Pure Love Labyrinth is a shoujo romance in the same vein as Special A, Voice Over!, or High School Debut: It's about a super-happy, little bit ditsy girl and the super-cool guy that she is in love with. There are two twists to this particular story, however. First, the guy in question is an actual idol, a popular actor. And second, he's her brother. (Given that this is a sappy shoujo romance and not a hentai or dark seinen drama, I'll leave it to you to guess if they are actually blood related or not.)
It's fun. It's sappy. The
main character is a ball of sugary sweetness that you can't possibly not like. None of the guys are jerks. It ends well (if a bit rushed). The drama is pretty low-key.
In short, it's everything you want from a sappy shoujo romance.
Is it perfect? Of course not. The last chapter should have been an entire volume, if not more. There was a male best friend character that they bothered to hint at as a possible romantic foil on two separate occasions... the only two times he ever appeared. The girl's female best friend has a romantic interest that comes out of nowhere and goes nowhere.
But all of that is beside the point. The point is to tell a sappy love story about two really likable people. And it does that very well.