I watched this drama two times.
The first time I was captivated by the intense plot. The first episode got me on its hook and never let me go. It was intense, Talay's actor performance was so expressive that I related to his character almost immediately. Then it came the romance and it was just perfect, since the first scene together Talay and Puen are between the most cute and warm couple I've got to see in a bl drama. Puen looks calm, stoic, while Talay is more clumsy, almost awkward. It's fun to see how the table turns when they get to know each other better.
I enjoyed watching their romance, some episodes doesn't involve the universe-travelling so much, but it's always enough to give the characters their own personalities and struggles. Some people call this drama "boring" because of this, but personally I got so immersed I couldn't stop thinking about how it was going to end knowing their parallel lives are so different from the ones in the "real" world.

The rewatched was the best. I felt the urge to come back here 'cause of the warm chemistry of the actors, but I found myself so much more immersed in the show. There are so many little details in the first episodes that make the later ones much more deep. The color palette change every episode and you can perfectly say why that specific color is so important in that scene.
I found myself hooked and it's so hard to watch the last episode again, knowing there won't be any other. I hope Our Sky 2 will get aired soon.

Long story short: give it a shoot. It's worth it I promise. If you're looking for a cute, romantic, deep and captivating show, this one is for you. If you're looking for something more "serious" or fantasy, you might not get satisfied - so I recommend to watch it with a different mindset and enjoy it.

Last shout out to the music team: you guys made a SPECTACULAR job.