This starts as a show about high schoolers entering a martial arts tournament. There is a lot of stuff building in the background about this evil cult trying to summon a god and those running the God of High School Tournament trying to stop them, but most of the focus for the first season is on the tournament and the participants. This puts the show in a position that to keep you engaged, you have to care about the characters and their struggles.
And the show quickly starts to fail at this, because our three main characters are all very generic. Just by me saying a generic lead in an action-oriented anime, you've probably already guessed there are going to be a lot of gags about the main character eating a lot of food. Sure enough, they are there, and the more time goes on the more you notice all of these characters are just walking bags of tropes. That isn't to say there is never anything there, when Daewi snaps for a bit it's a bit of an interesting insight into his character and a very violent side he has been trying to conceal, but it's quickly forgotten about which kind of sucks. It feels like it just happened so we had a reason to root for the main character, Mori Jin, over him.
Once the interest in the main characters starts to fall apart, you just start to notice so many things about this show that are stupid. Mira Yoo is the center of a few of them, noticeably her sword. She uses the 'Moon Light Sword' style, which is a sword fighting style (Weapons are allowed in this tournament). Almost every fight she ends up being disarmed from her sword, after which she proceeds to kick her opponent's ass because half of her techniques involve the use of no sword what-so-ever, and these are all the techniques that seem to be good. Because that's how fighting styles with swords work.
Also, there is a guy who just summons a fucking shark to eat people. Now while this is really, really fucking funny it just seems an odd choice for a martial arts tournament. Back on to Mira, several times she loses her sword due to dumb shenanigans despite this being a memento of her father. I hate it when a show does this so much (I love Fruits Basket, but they do the same thing with the picture and it's infuriating), it just doesn't feel like she cares as much about it as the show wants to portray.
There are so many odd moments that, while sometimes funny in how disconnected it feels, take away from the show. From the Shark summoning, swordless sword styles, fighting off the summoning of a dark god with a bunch of hippies banging on drums and a guy firing off several automatic weapons while throwing swords, I find it impossible to take this show seriously. At the same time, it's not insane enough to work as a spectacle, and that just leaves how good the actual fights are.
As the only real positive of the show, there are a lot of great fights. The show does a good job at making the characters all feel unique in how they fight, fights never feel like they drag on too long, and there is a lot of fun spectacle to the whole thing. While I do give the show credit for it's fun and interesting fights, they aren't anywhere near the best fights I've seen the past couple years, so to be the only motivating factor too keep watching it just isn't enough.
God of High School just doesn't have anything interesting to offer. The ideas are pretty common ones, the characters have very little depth if any, and there isn't enough spectacle to make up for the lack of substance. If you just want a show with some good fights and aren't looking for much else, it's a fine enough show to watch to kill time, but otherwise, I just say skip it.