I've heard it's basically ET if ET was the Cloverfield monster... I may need some convincing. 
And if you add The Goonies to that you're spot-on in terms of describing this movie.
I saw it yesterday. Glad I went to a matinee as opposed to paying night-time prices. I think it was just "okay", it wasn't something I would run out to see immediately. The acting from the group of kids was the best part of the movie though - everything else was stuff you've seen before.
Thank you. Finally somebody who feels the way I did.
Too bad an OK movie has backed up Trek like this did.
