If you're thinking about starting on this drama now that it's done, let me just share with you on what I thought about it.

First of all, reading the plot summary got me real interested in the drama. I mean it involves demon hunting so if you like action, this one is for you. If you want romance, then give this one a skip. There's no romance at all. Instead, there's more of a growing family & friends relationship.

Story: It's a slow beginning but picks up pretty quickly afterwards, especially when the counter's backstories come into play. I think only two counters backstories played a main role to the plot. The other two is more for a viewer to understand how they became a counter, which is unfortunate as the spotlight for these two seemed limited. For the first half of the drama, the plot moved at a good pace, numerous demon hunting scenes which is great because this is what the drama is about, and mysteries and unanswered questions were revealed.

But after the halfway mark is where a drama either make it or break it. I say more of break it because right around ep 9 or 10, plot holes began to occur.
* What a surprised (sarcastically)............... this involves political corruption. Figures.... since everything happened because of this. This is nothing new when it comes to figuring out the villain.
* A lot of questions came to play that seemed like the writers didn't focus on, which would've made scenes more understandable. I'm not sure what happen with the writer here because I found a lot of episodes a drag or stalling after ep 8. A lot of those episodes (especially ep 10) should've been handled differently, as you really could've just skipped some episodes and you wouldn't even know you missed out on something. I knew they changed the writer at Ep 13, which at least showed plot progressing a little bit, but even then, there were too many random things thrown in and only one or two sentences (if any) to describe what happened for the final half. You could also blame the announcement of season 2 for this mess that occurred after ep 8.
* We went from the counters hunting for demonic spirits in order to protect humans to just focusing on 1 for the rest of the drama. If this 1 demonic spirit was the head leader and the other evil spirits they hunted were under him, then this would've been okay but since this wasn't the case, this seems like the writer or director lost direction in the second half, like he was the only demonic spirit left, no one else in their area was demon possessed.
* Useless spirit partners. I mean I guess they lend them their powers (and wands) but all they do is sit at the table and discuss things. They only worry about their world partner if something happens to them physically. I just didn't see an importance to them, besides getting the counters (except for So Mun) out of a coma.
* The most evilest villain in this drama never had a demonic spirit in him until the last few episodes, even though he has committed murder and has thoughts of murder. According to the spirit partner's statement, anybody who has committed murder or desire to murder attracts a demonic spirit. So why wasn't he possessed a long time ago? That doesn't make sense.

But even after all of that, I still enjoyed this drama. I love the action, the closeness of a family the counters had for each other, the dramatic scenes of the demonic spirits being cast out, and the comedy this drama showed (more in the first half of the drama, fewer in the second half). Though they may have thrown some random stuff in and missed out some important details for us viewers to understand, at least I can say that the ending is satisfying and that there's closure.