Here's the back cover for Scooby-Doo! Return to Zombie Island courtesy of WBShop. The back cover reveals that the film will be 80 minutes, as well as that there will be two bonus episodes. "Mummy Scares Best" from What's New, Scooby-Doo? will serve as one, while very oddly, only part 1 of "Ghosts of the Ancient Astronauts" will be the other. I guess fans will just be left wondering what happens in part 2?
Here's another description of the film from the back cover:
Join Scooby-Doo, Shaggy and the Mystery Inc. gang as they win the vacation of a lifetime and put their mystery-solving days behind them. As soon as they arrive on the tropical island and check into Moonscar Island Resort, Velma, Daphne and Fred can't help but notice how strangely familiar this island is to a terrifying place they once visited long ago. They soon find out that paradise comes with a price when they encounter an army of zombies and creepy cat people. Hop on board and travel with Scooby-Doo and the gang as the unearth the mystery of Zombie Island in an all-new original move adventure - 20 years in the making!