Art - 9 - Everything is quite well drawn. I have no complaints.

Character - 7 - I'm pretty easy to please as far as character development goes, but I often had trouble telling characters apart

Story - 8 - Now this is where things get difficult. I think that the story presented here is a solid 8; it was very good. However, it was incredibly poorly executed and hard to follow. There are so many instances where the reader is presented images with no context. I can't tell if the author is neglecting to include critical information where it matters, or if they are failing to execute some kind of plot twist, but the result is that I was constantly jumping back pages to see if I had missed something (which, of course, I had not). I feel like a lot of this manga could have been saved with more narration, like if the characters would say what they think is going on.
The author is also very bad at conveying where certain things are happening within the facility. For example, without spoiling too much, towards the end of the manga the workers are being pursued by a threat and it's a very fast-paced situation. But then all of the sudden they sit down and start planning stuff and everything's chill for like a week, so we're left to assume they've gotten to a room that the threat can't get to? But then people seem to be able to go get things from other rooms without a hint of worry. And then the threat appears again in the main room we thought was safe with no explanation of how. They just completely fail to establish where the threat is and why they're safe in some areas.

Overall - 5 - I found that this manga had nice art and a gripping plot, so I can't outright call it bad, but I still would never suggest anyone read it.