This is pretty much copy pasta that I just posted on Metanorn:
OK. Just watched the Campione pre-air.
First: Animation quality it pretty good. I suspect that the full version will be even better.
Second: Characters. So far they seem to be cut from the basic of tropes, but they do have something...
Third. Exposition between the workings of the Heretic Gods and humans is just damn intriguing. This exposition was very well weaved into characterization of our main leads, and the supporting cast.
Fourth: Solid magical stuff. None of the arcane stuff should surprise an average anime fan, but they do put a good spin on it, and make it their own.
Fifth: I like these two main characters; earnesty goes quite a long way for the female lead, and sheer guts for the male.
In essence it looks like solid entertainment. It has a good deal of eyecandy for the female lead, and the male lead doesn't look like a complete dork. The romance starts in the first episode, and that, in and of itself, is something of a draw. She really digs this guy for reasons she may not be aware, so expect a slight tsundere attitude from her, with the compliment WTF from the male.
IOW: I had middling expectations from the show, and it managed to exceed them. I'm glued.