It’s about 65 percent of a good alien invasion movie, but Dark Skies fumbles the ball by not revealing enough along the way. By the time the characters finally accept that what’s disturbing their home and children are beings from beyond our planet, more than an hour has passed and director Scott Stewart leaves himself very little time to wrap it up convincingly. The film needs to cut about 20 minutes of suspense building or it needs to be 20 minutes longer to give itself somewhere to go. A lot of that tension is triggered by neither Lacy (Keri Russell) nor Daniel (Josh Hamilton) wanting to accept that aliens even exist, and their skepticism helps keep the movie grounded. It just plays around with it too long before acknowledging (in the movie, at least) that aliens are real and dangerous.