Revealing mistake: It's stated that Achilles has been killed. He then is shown lying face up on his pyre. But if you look closely enough (zooming in might help) you can see that he's still breathing.
Audio problem: Having just captured the pig, the soldier with a knife says "I'll stop your squealing" but his lips don't move.
Continuity mistake: Throughout the battle in the throne room at the end, the position of many of the dead suitors changes between shots.