Almost all of the info they talked about is stuff we already knew besides like Eriko having to record her songs before knowing the story and nerds getting robbed at the arcades.

They noticeably left out things like Hibiki and Takane being cut from the arcade, Xenoglossia replacing all the voice actors, Yurishi retiring, Julia/Rinko/Reika being cut from 2, and their attempts at overseas activities.

Also the editors added "(Only in 2)" to the telop when GamiP was talking about how idols became unproduceable in the sequel, but at that point Miki had already become unproduceable in SP.