King Mario of Cramalot - S1-E2
Audio problem: When Toad says "that was close", his mouth isn't moving. (00:11:29)
Other mistake: In many of the live-action segments, the Alarmtron logo on the alarm in the Mario Bros' residence has been partially covered to read "Acarmtron" instead. In addition, in several episodes, the phone number for Alarmtron is also partially covered.
Other mistake: In the theme song, there's a part where Mario touches a star and gets fire power. The star is suppose to give hyper power, it's suppose to be a flower to give him fire power.
Robo Koopa - S1-E52
Continuity mistake: At one point, Mario asks Dr. Nerdnik how to stop Robo Koopa. The doctor walks in circles, and in the next shot, he is in a different position. (00:06:40)