One-Punch Man

[Ryllharu]

While what you said is true on many levels, and well written...what you still fail to grasp is that this series is satire, bordering on outright parody. The clear difference is that this is not parody, but absolutely satire. A key but important difference.

Unsatisfying shonen build-up (and lack thereof) is what this series is all about.

We as the viewers know Saitama will defeat his foes in a single punch. We now know that he thought he worked hard to become what he is, but no one else thinks so. He's simply absurdly strong for no rational reason.

But deep down, we watch with baited breath for the moment that one punch isn't enough.

It's no deconstruction. It is outright criticism. All the build up, all the training montages, all the near victories. This series spits in their face.

edit 2:
Just so this is abundantly clear, a parody of shonen/seinen is TTGL/Gintama. They exaggerate and play up the absurdities of the genre. OPM is a satire, it insults the hallmarks of the shonen genre by emphasizing and elevating the opposites.