During the performance of "Express Yourself", a jacket at the end of the stage appears, disappears, and then reappears.
Film is flipped briefly during the "Ray of Light" dance performance. During a close-up of high kicks, look for graphics that are reversed on the wall signs.
During Finn and Rachel's Madonna medley, the pieces of the drum kit Finn is hitting do not match the sounds of the drums in the music.
Madonna did not write "Like a Virgin", despite what Brittany says. It was written by Billy Steinberg and Tom Kelly.
When Santana and Brittany are talking about Santana dating Finn because he's younger, Brittany says that his birthday is three days before Santana's. This would actually make Finn older than Santana.