This series begins with a very funny episode #1. I wish it continued this way, as it would have become a classic comedy. Never the less, the series does have some bits of comedy mixed in throughout the series. I give Season 1 a high rating, but the remainder of the series is not as good. After season 1, the story is overly ambitious, it seems to meander, and they emphasize too much fan service, and too much blood and gore.
This is mainly about science fiction, philosophy, politics and religion. There is lots of action. There are some interesting ideas and discussions about science versus magic, geopolitics, and personal values. The character development and pursuit of redemption are strong elements in the story.
There is an overabundance of boobs and panties, which I think detracts from the story, and may offend some viewers. I know "fan service" is common in anime, yet it seems to be excessive here. It seems like they show someone spouting blood and falling down, then they are rewarded with a look up a girl's skirt at her panties before they die.
There are many dramatic battles, but the extreme violence, dead bodies, blood and severed limbs detract from the story. If a university had such a high death rate, I can't imagine any parents allowing their children to go to school there! These negatives definitely reduced my rating of the series. Watch "A Certain Scientific Railgun" as a fine spin-off series that does not lose its way.