Revealing mistake: When they are escaping in the beginning of the episode, watch Rodney dial. As he finishes, one of the DHD address panels pops out and falls off.
Revealing mistake: Season 2, episode 2 "Virtu-Date": When Pim is jumping rope with the girl, she is building a card house. When she jumps you can see the tape holding it together.
Don't Fear the Reaper - S2-E39
Revealing mistake: After Jaden summons Dandelion in defence mode, he places a card face down. When he goes to insert the card into the slot on his duel disk, his hand doesn't appear to align with the duel disk. His hand appears to pass over the spherical red light on the duel disk, and not the card slot. (00:13:02)