FWIW only the first chapter is that long, the subsequent ones are about 30 pages. This is the same author as Hinamatsuri, so it's going to be a mix of drama and situational humor more-so than cracking actual jokes.
For example, the 2nd chapter features the absurdity of:
Megumi agreeing to do 3 hits in a single day, yet Mama expects Megumi home by dinner. So J is forced to sprint around town on a kid's bike with helmet for safety, in a mad dash to finish all the contracts. Because nobody ever wants to get on Mama's bad side! /s