This manhwa is not for everyone, but it can be very rewarding for those who enjoy things that are different.
Be aware that it takes a while to take off: this is a story where the sum is greater than its parts. It takes a while for each episode to seep in, settle down like a layer in your psyche, and gradually turn into a watercolor painting of emotions. The theme of this painting is not really any particular people, but the idea of Love, which here includes familial love as well as romantic love. (Pardon the cheesy painting metaphor, but it's the best way I could describe it.)
Before starting this manhwa, you might ask yourself what you are looking for. I liked this series without caring too much about its flaws because it had hard-hitting substance underneath the strangeness. I was patient with the fact that the main couple was not really focus of the story. The first few volumes may give off a rough-around-the-edges, disjointed feeling because of the seemingly unrelated stories, which at one moment might be a dramatic tale about aliens traveling through time and space, at another moment a comic interlude about high school students. But if you suspend your need for logic and order, you might feel your mind expand in an exquisite dreamworld, full of wit, charm, and poetic twists of fate.
When I finished the last chapter, tears unexpectedly welled up in my eyes. It was not a tragic ending, but the beauty of it left a deep impression on me.