An old-school action popcorn film. Pure and simple.
I won't recap the plot or anything but observe that Odenkirk has a lot of fun in this and is great in a kind of "nobody" sort of way. John Wick he is not, but he nails what he is supposed to be. Everyone looks like they're having the time of their lives in this. Especially Christopher Lloyd. And that's so much better than cheesy action films that take themselves too seriously.
The movie is 91 minutes. There's not a lot of time for story or exposition. And that's fine. There's enough comedic beats and the movie is aware of how patently absurd it is. Every time Hutch goes off monologuing someone literally dies- that's how irrelevant the story basically is and the creators are aware of it.
You're there to see Christopher Lloyd grinning maniacally with a shotgun in his hand, you're not there for even the world-building of John Wick. There's hints of world building there- Hutch's wife Becca *obviously* knows his past. As much as I want to know about that, I'm fine that they never explain why she's so phlegmatic about super-gluing knife wounds back together. But this movie doesn't even show a world like Wick's, it just whispers it in the quite moments before someone gets beaten to death with a bus railing.
And being free of even that light blanket of restraint, I'll say that Nobody is better paced than John Wick 3 was. Wick 3 had the problem of being intended to be the final Wick film and instead is turned into the midpoint. Because Nobody is so bare bones, it can focus on pacing- the plot, what there is, serves as breathing room for action scenes. It's not complicated moviemaking, but it does precisely what it needs to do.
Finally, this idea of action films being stuntperson-driven, with intense actor training for long, complicated action shots is a winning formula. Keanu Reeves established this with John Wick, and if they can make Odenkirk into a murdering machine it shows the formula has legs. I'm looking forward to seeing them work the genre and explore today's set of actors who are willing to undergo intense stunt training to do these kinds of movies. They are breathtakingly more entertaining than the CGI pileups of the Marvel movies and are probably a fraction of the cost too.