Continuity mistake: When Ben and Gwen are fighting off aliens on Incarcecon, right after the tetramand destroys the hoverboard, the Omnitrix is missing from Ben's wrist.
Continuity mistake: When Gwen tries to land Tetrax's ship on Zenon, the numbers on the holographic heads-up display remain constantly readable to the audience. In the shots where Gwen is seen from the front, however, the screens show a mirror-inverted image, so the numbers should logically be mirror-inverted as well.
Plot hole: I can somewhat understand that in a kiddies' show all aliens can inexplicably speak English - but using Terranean (i.e.: Arabian) numbers as well? While Tetrax's computer uses alien runes, the readout on Gluto's holographic HUDs use Arabic numbers - somewhat a bit too deliberate a producer choice to emphasize intergalactic communication.
