Resident Evil 5: Alternate Edition has two extra episodes. Lost in Nightmares is a flashback where Jill and Chris infiltrate Spencer’s mansion. Capcom hasn’t said much about the other episode, but the title may have leaked out.
A detailed report on Resident Evil 5: Gold Edition – a retail release of Resident Evil 5 with the Alternate Edition content from the BBFC lists Desperate Escape as another new level (thanks for the tip Lyn!!). There are only two new levels in Alternate Edition and Lost in Nightmares is one of them, which means Desperate Escape must be the other.
No other details to report at this time so you’ll have to imagine what Chris is desperately escaping from.