I heard it's good, but I'm not a fan. Tried to read it a few times and every time it felt a bit overwhelming. I think I just haven't grown up enough to understand it's wonderfulness

Wow, so manga "Oyasumi, Punpun" is like Goodnight, Angry? Cool

You can try any manga by Inio Asano. Everything that he wrote is a depressive masterpiece. If you read it from the start of his career you can even see his progress