Visual noise is a good word for it. It’s very rough and the scratchy lines are very similar to sketching but less clean. One of the newer mangas that really wades back and forth between clean lines and that scratchy style is JJK. Sometimes I really like the art and sometimes I’m thinking, “What am I looking at?lol”
The comparison between Genos and Saitama is funny—one tries to purposefully exceed being human by becoming more machine, while the other accidentally surpassed the limit but somehow still stayed human-like. I love how imaginative OPM gets when creating different monsters and super powers, which all seem useless in the face of Saitama basic abilities: infinite strength, speed, durability.