The riotous antics of angst-ridden, disaster-prone middle school student Greg Heffley continue in “Diary of a Wimpy Kid: Rodrick Rules,” focusing this time around on his complicated relationship with older brother Rodrick. A spikey-haired high school student, Rodrick is lazy and undisciplined and spends way too much time practicing with his rock band, Löded Diper. While he loves to torment Greg, he ultimately has a deep affection for his younger brother.