Doofenshmirtz claims he did the the wombat ad as an adult in the 80s to finance his first inator. However, he was previously shown as a child entering his first inator in a science fair.
Candace claims she has won the last 12 games of Skiddley Whiffers in a row, but the chart she pulls out to prove it shows she won 20 games in a row (much more than 12). The same chart is said to cover 24 games that Candace has played, but the chart only lists 23.
When Candace takes her video camera to show her mom, it doesn't work because of the pop up adds, so she throws it in the sink, but when she takes her mom out to her bicycle, the camera is back on her helmet again. In the next scene it is gone.