Doug Takes a Hike / Doug Rocks - S1-E4
Continuity mistake: When Roger is dancing in Skeeter's yard, he changes color.
Doug to the Rescue / Doug's Cool Shoes - S1-E7
Continuity mistake: Doug's Cool Shoes: When Doug is buying shoes, the saleslady takes off Doug's sneaker and when it shows the shoebox, his other shoe is already in there.
Doug is Quailman / Doug Out in Left Field - S1-E12
Continuity mistake: The baseball players on Patty's team appear out of nowhere near the beginning. She walks back to the bench in defeat and it's just Doug and Skeeter. A couple of seconds later there are a lot of people in the stands.
Doug to the Rescue / Doug's Cool Shoes - S1-E7
Continuity mistake: Patty's notebook disappears and reappears when she is being bothered by Roger in detention.