Continuity mistake: When the monster puts down Hanso after she tries to escape, you can see her footwear is completely dirty, but in the next shot where the monster's tail uncoils itself from her body, you can now see the pink and white of her footwear that you couldn't see before.
Continuity mistake: Near the beginning, after the monster drops from underneath the bridge into the water, a crowd of onlookers approach the waters edge. As gang-du joins them he drops a can off his plate and picks it back up and places it back on the plate. The shot then changes to a close-up and the cans have rearranged themselves. (00:12:48)
Revealing mistake: When the American man throws a square concrete tile at the monster it reacts (moves its foot in pain) before the tile actually makes contact. (00:16:11)
