Let's start with the good.
- First ever instance of two popular western artists writing opening and ending score SPECIFICALLY for a japanese anime (and doing a damn good job at that)
- Weekly live streaming of new eps on twitter for everyone to watch FOR FREE
- Production I.G. getting the animation right when it comes to weapons and monsters
Now comes the bad.
- Slow and janky plot (5 eps to get past the entrance exam and random timeskips, like the three month period where Kafka was being a kaijuu on the run but casually managed to pass the written test he had been failing for a decade)
- Dull and derpy character design (don't wanna be a hater to the anime artist but why he gotta draw such goofy faces and gummy bodies, I still have ptsd from the latest seasons of Naruto Shippuden) with lifeless coloring and goofy military equipment
That said, I believe the biggest problem of this anime is the main character.
MC being a grown adult and still acting like a cringe middle schooler is frankly unwatchable. What makes the situation beyond incomprehensible is that the rich elite girl is somehow falling for him? I get it she knows he can be really strong (and she might have a thing for monsters..) but can't dude act normally in the day to day without insulting all the 30 somethings watching this? (I'm in my mid twenties but the second hand embarrassment is real).
This guy grew old with the idea that he absolutely has to be the lead superhero (and for a shallow and tropey reason imo), and now he's showing how pitiful he is at it. He only got a second chance because he randomly ingested that mutant mosquito and became OP, but he wasn't naturally strong or resilient like other shonen mcs. If there is something that he does well is monster analysis and strategy, so why not accept your expertise and cultivate it in the support backline like the computer girl? His stubbornness is not admirable, it's dumb and immature. His "heroic" deeds he can only perform with undeserved monster 'roids, while as a person he hasn't grown past eighth grade. Instead of inspiring his younger colleagues with his life experience he chooses to pass as the goofball to avoid sinking into self abatement and confidence issues. His whole character reinforces the age related insecurities the watcher might have and normalizes being a manchild as "comic relief", with the catchline "mc is in his thirties" being meaningless bait. Only thing dude thankfully hasn't done yet is being a creep with teenagers because it would have made me drop the show instantly.
All the other characters so far have stayed in the background and are quite forgettable (hair color is the main way to tell them apart). Shinomiya's character dynamic as tsundere is predictable and I'm afraid Ashiro will end up doing the same by the end of the season, falling for the MC for no reason (if she hasn't already).
The only character I do like is Hoshina. Looking like the underdog airhead but being the coolest person in the room, a good team leader and Ashiro's right hand man. Cracking manzai jokes one moment and dicing kaijuus the other. The different sides of his personality coexist harmoniously without the cringe contrast of poorly timed comedy as it happens in other parts of the show. Him teasing Kafka but then actually showing jealousy for Ashiro in episode 5 was my favourite funny scene so far.
All in all, this series had potential and good production value but it can't seem to take off and it is leaving me disappointed.