Ogeha sure is a strange manga. I wouldn't say it's bad, but it's not what I'd call a good manga either. It's… Particular. Here's my first review.

Story : 5
There is no real "plot", but there are some events, and some development.
Ogeha is a very short slice of life, between a bug and an adolescent, so there isn't much more to say on this point.

Art : 8
The main (and maybe only) quality of the manga. The art's clear and has precise traits, without looking too simple.
Also, I particularly like this style, it reminds me of Summertime Rendering.

Character : 7
This is quite an interesting point. The main characters are Ogeha (obviously) and Kijima. While I don't have much to say on Ogeha, Kijima is different.
He is portrayed as an insensible person, who doesn't pay attention to anyone or anything except himself, and is NOT a good guy. You could even say he's a bastard, considering what he did and how he treated Ogeha. But in spite of that, he still has some development in his relation with this strange bug-looking alien, and I found that interesting.

Enjoyment : 6
This is not really a manga you enjoy while reading, it's even pretty disturbing. But there is an evolution in the story and I can't say I wasn't curious about what would happen.

Overall : 6
This manga is a bit particular. It's not really good, but it's not completely bad, and there is something interesting, something special that makes the manga not a complete waste of time (even though it's probably just my curiousity).