There is no "twist" here, any more than there was in The Last Airbender. People keep forgetting that Shyamalan didn't conceive or write this film -- he was just brought in to direct someone else's project. Sure, he did do a draft of the script, and as the director he had the final say about its content, but one theme I'm seeing in a number of those Rotten Tomatoes reviews is that Shyamalan's direction seems phoned in because he wasn't sufficiently invested in a concept that wasn't his.
So while this is a film directed by Shyamalan, it is not a "Shyamalan film" in the sense of following the formula he's known for.
So it's *not* boring and nonsensical like all his other films post 'Unbreakable'? Because I'm hearing different here.
For the record: didn't see it, ain't gonna. It's sad because I was a big fan of MNS about ten years ago. I rather enjoyed 'The Village' and somehow overlooked the monumentally insulting stupidity of 'Signs' but now...well let's just say Airbender used up what last lingering dregs of respect I had left for the man as a filmmaker.