I agree with one of the reviewers, felicismoon for her final review; but somehow I need to pinpoint/add some of my final thoughts for this as well. Believe me, I'm among the anticipated viewers that somehow feel like, this can be on-par along with Space Sweepers (also space-themed too, coincidentally released in the same year, early), based on my first impression of the plot synopsis and main posters; but I was wrong, from the very start.

Cons as given:

1) VISUAL FX GOES TO OLD TIMES (literally)

since this is basically focused on outer space that I found it mildly infuriating that they tend to forget by giving attention to Earth, in detail, graphically. Early episodes are a wonderful mess that seeing those buildings in a city reminisce me back to the late 2000s to early 2010s, and the drought textures.... am I watching 90s music video? And so I researched the studio who made this drama, but out of the web browser's radar, to my dismay (even you as a viewer can easily photoshop that too with given tutorials) [watch back and pause as evidence. screenshot too if you want]

*as for the intro sequence, mayhaps Netflix nailed the job to explain the drama summary in one whole video. Correct me if I'm wrong by stating which graphic studio that did so, because they did an intro sequence for Hellbound as well, and I genuinely love that too, that leaves me hauntingly wonderful.

and don't make me compare to Space Sweepers' overall top-notch visual effects; you can (barely) see the differences either

2) PLOTHOLES

as some suggested, there should be a side story/prequel of how it has to have happened from the water itself. And Luna, too (just a picture, then the progression; no backstory, ouch). And also from me: lack backstory of how the drought even started, and that Director Choi's backstory. The direction for the storylines is pretty much complex (bear me, I'm alright with throwbacks in-between from each episode, but I genuinely don't understand, visually, for some lines from their interpretations). Other plotholes have been explained from her, so I don't need to recount

The only pros I can point these out is that yes, the stellar casts save this drama. Not instead of main casts, the supporting/cameo casts too (Kim Sia... she left me wow on this one). All of them, so I'm totally agreed with this stance. Thanks to their marvelous immersion in acting, overall the drama is pretty decent. So does for the BGM or OST if I missed out. Hence, the final rating of this review (a little high than her, because again; the casts made the job well done)