Story-wise, the plot hardly makes any sense at all. Near the end of the series, the girls have the contact information of their families, and photos of friends and family in their pockets, yet they don't seem to have contacted their families, or even recognize any of the reincarnations they encounter. As for the mystery of Red Garden,, they would have known at least, that they were students on the island, since they had their student IDs on their bodies when they lost their memories. All mysteries about their immortal bodies would have been easily answered by Paula, who knew where they were going, and that they would lose their memories.
Also, the theme song is pretty bad.