Review covers up to the end of the Monster Association arc, which just finished at the time I'm writing this review (chapter 170)

When I first watched the first two seasons of One-Punch Man, I was hooked by the show. For me, what made OPM unique is its protagonist Saitama, who thinks his life is boring and yet accomplishes incredible feats with his strength. Unfortunately, the rest of the story delivered through the manga is absolutely forgettable.

The good
The art is breathtaking. Pannels are very detailed and since fights take place in vast areas with big enemies, OPM offers some amazing sights.

Although there isn't a lot of comedy after the first chapters, it often delivers when it's there, thanks to King and Saitama especially. I also like the fact that Murata kept the art style of the Webcomic in some pannels to add to the comedy.

I love the extra chapters! They have a nice Slice of life feel. Kinda sad that there hasn’t been any new ones for a while though.

The bad
Characters are very weak. Although Saitama can be funny at times, his characters is just "I act dumb" so that other heroes and enemies underestimate him. His sidekick/student Genos is sometimes straight up annoying. He takes everything Saitama says seriously and makes a fool of himself which is not funny. Other than that, all other heroes (except King and Fubuki) are so unimportant and forgettable that we might as well name them hero #46 or hero #72 (Like who cares about Class C: Fart Sniffer or Class B: Copium Injector?)

The plot is...repetitive and predictable. Every arc goes the same way. An enemy emerges out of nowhere, heroes fight it and Saitama comes and delivers the final blow. Then we discover at the end of each arc that this enemy was not the one that endangers the Earth as the oracle said.

I mentionned earlier how forgettable characters are. This is also due to the fact that fights are absolutely boring. For the entirety of the last arc, we follow a fight between a hero and a monster, then move on to another once it finishes. This keeps going for chapters and chapters, it never seemed to end. Did I forget to mention that these monsters have no personality whatsoever? Also, why are these fights the focus of the majority of the manga when we know Saitama will win at the end no matter what? The fights themselves are flashy and very well-drawn, but have no substance to them.

The story was initially about Saitama and his boring life and as I said, that's what makes OPM special, but then he just disappears and comes back for a couple chapters at a time while we focus on these dragged out fights. So disappointing. Side note: where tf did Sonic go?

**Spoilers for the end of the MA arc
My last complaint is about Garou. The number of times this man nearly died and came back fully healthy in minutes is just incredible. This guy has the heaviest plot armour I've seen and it's unbearable. At the end, his fight with Saitama was just about elevating power level, which seemed like a boring Dragon Ball showdown. Also, what was that retcon at the end? Absolutely garbage, didn't know the Phantom Thieves existed in the OPM universe.

Conclusion
Some people will say that this manga is not supposed to be taken seriously and it's just a comedy, but it's not. I never felt like the focus of OPM was its humor. Now I didn't read the Webcomic, but I imagine that it would be more enjoyable because at least it's more focused on the comedy, which lowers the importance of well-written characters and story. So yeah...good beginning, bad everything else.