After their first meeting with Angie under the bleachers, Greg makes an excuse about hearing the whistle signaling the end of P.E. class before dragging away Rowley by grabbing his right wrist/hand. But in the next shot as they retreat, Greg is shown leading Rowley by the left wrist, not the right.
When Greg first enters class on the first day of school, Greg Heffley is written on the blackboard. In the next shot, it is gone. In the shot after that, he writes his name on the board.
Chirag Gupta: The "Cheese Touch". No body knows when or how, but one day that cheese mysterious appeared on the blacktop. Nobody knew who it belonged to. Nobody touched it. Nobody threw it away. And so there it sat, growing more foul and powerful by the day. Then one day, a kid named Darren Walsh made the biggest mistake of his life.