SOME SPOILERS AHEAD

NieA_7 is a short, simple, 13-episode anime from the same studio as Serial Experiments Lain, Triangle Staff. Although, it is absolutely nothing like Lain.

The story is about a girl named Mayuko, an incredibly poor cram school student who lives in a bathhouse on the verge of being bankrupt alongside her friend NieA, a freeloader alien. Unlike the other aliens in this show who have an antenna on their heads, NieA doesn't. Because of this, she is considered an under seven, a class which is far below the ranking system for aliens which only acknowledges high-five to under-five, and anyone below under-five basically doesn't exist in any official database (unless they register as an under-five). Their relationship is that of Mayuko is the serious, shy, secluded girl and NieA is the loud, innocent, airheaded friend.

NieA_7 is... a strange series to think about. It's a very hilarious show. Despite it having many old cartoon sound effects and jokes that sometimes don't really land, it had me laughing in any moments. The show becomes a bit more serious toned as it goes on, dealing with topics such as the mundanity of life.
On the other hand, NieA_7 just has so many pieces of incredibly important information of its story that are missing about it. For someone like me, this would usually be something that I really dislike. The show doesn't answer any obvious questions that the viewers might have about its world, like the origin of the aliens, or the reason as to why NieA doesn't have an antenna like other aliens. It chooses to ignore this, and similar as to how the humans in this show quickly settled into living life with the aliens, you eventually just kind of forget that this is a question you had in the first place. Until you reach the ending of the show and you remember why you felt like as if something was missing from it. And yet, you still feel fulfilled with it, as if maybe those questions didn't really matter in the first place.

Most of the characters in NieA_7, despite them not being thoroughly developed or anything like that, are all characters that are always really enjoyable to have on screen. You have Kotomi Hiyama, the manager of the bathouse that Mayuko and NieA live in and also has. She's a very energetic person who, despite the bathouse basically always bringing in negative profit, tries to find ways to make the bathhouse bring in more customers. You also have Chiaki, who is a friend of Mayuko from her cram school and is also an alien-obsessed lunatic. Genzo, a childhood friend of Mayuko since the age of six who also has a crush on her. and Chie, the daughter of a restaurant owner who is also in a similar situation to the Enohana Bathhouse (although we see them actually getting customers in the show more than the actual bathhouse so). The rest of the cast is not very remarkable to talk about.
The art of the show can sometimes feel like it was very cheaply drawn, and the music of the show is very subtle and chill. It has a great ending theme song, and probably one of my favorite ones as well. The opening of the show however uses a very strange song. The singer just has this really raspy voice that I'm not a big fan of, and the instrumental is just really nothing to write home about.

Overall, I liked NieA_7. It's a funny slice-of-life anime with some decent drama elements here and there and a cast of characters that are mostly always fun to have on screen. It really immersed me in its world, even though it also left me with questions about it that I will most likely never have answered. But honestly, that's fine. I don't mind it.