Recommendations: read a good superhero comic. watch a good superhero cartoon. watch a good superhero movie, animated or live action.

This series started as a comedic/parody manga adaptation of a comedic/parody webcomic. As it goes on, the series has become much much longer than it ever needed to be. One Punch man is right now a full on battle shonen with all the cliche associated with it. It has an overpowered protagonist, lots of bullshit power ups, villain groups, tournaments, long dragged out fights and more.
It's comedy has completely run stale and telling the same joke over and over isn't funny.

It has led me to believe that the author has seen this and took the series in another direction.
It is still very much complete shlock and not in the best kind of way.

I appreaciate art, so I will say that the series still very much looks great and has highly detailed art. It's generic stuff, monsters tend to have lots of spikes and look like what you'd expect from a generic monster but done in stunning detail regardless.

At this point nothing separates it from the other run of the mill battle shonen except it has really pretty art. It doesn't have a story to tell, it isn't following a plot at all and has no interesting characters.