This is a bit of a result of half-assing two things instead of whole-assing one.

The concept is very compelling, and it's a cool execution of it at the surface level, but it can't really decide what it wants to be. As a faithful representation of the human body, it does a decent job, but fails to adhere to its own rules at times. As a good narrative, it also doesn't do a very good job, with a heavy focus on simply depicting how the body responds to certain phenomena. There are ways to make it interesting, but it comes off as highly formulaic here, and every time they attempt to have a bit of an interesting plot point or layering character dynamics, it feels 1 dimensional and doesn't neatly tie into their cells-as-people concept.

You know that a metaphor isn't neatly working and is kinda forced when instead of being able to show how something works after establishing the link, they have to directly explain to you how the thing works. The point of a metaphor is to say two things are the same, so that you can transfer your understanding of that thing onto the other. It's what allows you to show without telling and make the audience not feel stupid. In this case, they consistently feel the need to explain to you exactly how everything works, which undermines the point of making a show about comparing the inner workings of the human body to people in a society.

The last two episodes really bring these problems to the forefront. It repeatedly introduces new things you've never seen before, explains what they are, shows that happening in the show with a slightly tenuous link, and failing to deliver on a genuinely compelling story. There's a lot of character beats happening that seem like they're happening just because the writers had seen better media do it without actually building up to earn it in the first place.

I also just don't really like the way this show looks. The art style is kinda ugly to me. I don't like the giant rim band they put on the side of all the faces, it makes them all look like they're being lit by an extremely large and bright white light source from the back while their hair is flat as a board, it just doesn't look very good. That, and the animation is pretty low quality throughout.

If you really wanna learn about how the inside of the body works and don't care about experiencing a decent story, you might get something out of this, but the novelty of the concept wore off for me about 4 episodes in and I was hoping it would get better, and it didn't really.

My verdict, it's a cool concept on paper with a mid execution. They should've worked on the story more and wrote some more compelling characters within the world, or committed to the concept harder and made their metaphor strong enough to avoid needing to repeatedly explain it every time something new happened. In theory both could've been achieved, but that's also pretty hard to do, and I don't think this writer(s) really is at that level.