I first started reading the manga mainly from the style and expressiveness of the character design, and the anime did not disappoint in that regard, especially during the fights and fluid and weighty movement. And the banter between Okarun and Momo is the other highlight as they have a contentious friendship with a burgeoning romance underneath it. I don't see many relationships having something like this that doesn't feel forced or tacked-on, but Yukinobu Tatsu balances this and makes it feel realistic, between them and all the other characters. Even in 12 episodes, plenty of ridiculous shit happens that everyone accepts fine at face-value, and the realistic interactions ground everything else going on. Tatsu's design for monsters and enemies, of the spirit and alien variety, seem to come from taking something real and making a caricature of it, and working from there. In the last episode that's most obvious as those enemies sit in the middle between the average middle-aged Japanese adult and exaggerating those features into something grotesque. Seeing that inspiration is cool to see just by itself.
Dandadan doesn't have the same structure as other shonen battle anime, but it's great at having all the moments of humor, action, idiosyncrasy, and tragedy all available from one episode to the next.