I know a lot of people will say "this is just a kid's movie", and "it has a good message", etc, but this movie was terrible.
First, the parents are completely unbelievable. Are they oblivious or what? OK, the rocks and stuff could be "toys" found on the beach; but the girl walks around with a new stuffed rabbit, and no one wonders where she got it? The father said he was going to talk to the babysitter about what happened. If he did, didn't she tell him what happened? Or did he not follow up, and just forget about the whole thing.
Second, major plot holes: how did they get to the island after the escape. They had to take the ferry, no? Why didn't the authorities stop, or at least alert the ferry operators (assuming it was even running at that time of night). The kids had powers, but didn't seem to use them. If you had super powers, would you show them off? Third, the movie could not decide what it wanted to be, and it stole from a lot of better movies. Obviously "ET", and "Close Encounters" come to mind, but you could spend the entire movie going, "I remember that scene from (insert sci-fi fave here)" Anyway, I am sure that this will be a big hit, but just be warned.