The first episode is a direct continuation of Matt Reeves' The Batman and I imagine those who haven't seen the latter will be a bit lost. But I watched The Batman a while ago and this show did an admirable job of quickly re-familiarizing me with where the movie left off, and without getting bogged down in a didactic recap. It also recaptures the movie's aesthetic and grim tone nicely, although the show has a lot more moments of sly levity than the movie did.
As in The Batman, Colin Farrell does an excellent job portraying The Penguin as a stereotypical mafia "street guy:" uncouth, profane, mercurial and quick to violence; but also savvy, cunning and able to read people. The character might have absolutely nothing to do with the comic book version but he's interesting in his own right.
I have my doubts about the show giving The Penguin at teenage sidekick; and I don't know if The Penguin's machinations will be enough to sustain a whole season. But so far it's off to a great start.