Overall, this is a pretty good anime. I'd recommend it. Its definitely not for everyone. There's probably few people who are into everything that this show has to offer *cough* but if you're not into any of it at all, then you're probably not going to want to watch it.
Visuals - The animation is surprisingly fluid, and the overall direction is actually great. This show plays around with animation styles and aspect ratios, and in all seriousness has a distinct energy to its visual style. All these elements combine to make the ecchi fun that more effective. My only complaint with the visuals would be that for some reason the protagonist has no pupils most of the time. Its not even a bad thing, and you get used to it, but its just a bit odd.
Characters - While these aren't the greatest written characters on the planet, I've got to say that they are actually fairly well written. Except for maybe one or two characters, I can't think of any that fit into any of your typical anime archetypes. Not that I can tell, anyways, and I'm fairly familiar with most of them. Even the protagonist isn't your typical blank slate audience surrogate that you get in these types of shows a lot of the time. He probably could've used a bit more development, and we could've gotten more information on him, but he's still a character.
World - I don't have a lot to say about the actual story, as there isn't really any ongoing narrative. Every episode has its own thing going on and overall the show is mainly a slice of life structure. The world building is actually pretty good for the most part. There are some things that they could've focused on that they didn't (although most of the things I can think of would just become irrelevant). I like the effort put into creating all these different types of monsters and how this world functions. (At the very end of every episode there is a short title screen giving some extra info on certain species that also helps with this.)
This anime was a lot better than I was expecting and I am looking forward to a season 2 if there is one.