It's a long movie - 2.5 hours, and the time went by quickly enough, so somewhat entertaining at least, but I was hoping for something much better.
What spoiled the movie other than a lame single-dimensional plot (it's basically a chase movie - government hunting down a leaker) are (mild spoiler alert) :
1) It's utter reliance on a magical alien device that gives whoever holds it a bunch of superpowers.
2) Some really poor CGI of bug-eyed aliens (their only appearance for maybe 1-2 min out of 2.5 hour movie)
What would have made a better move would have been to cut the magic and make it more believable, much more focus on the cover-up - what the government was actually seeing/collecting/studying etc, maybe more like a documentary than fantasy. MUCH more effort should have been put into the CGI, and the aliens could have been a bit more imaginative, not just bug-eyed air-breathing humanoids.