All I remember is that this movie stars 3 kids. Two boys and one girl ages 10 to 12. At the end, the boys square off to fight on a rooftop with one having a switchblade knife. Before they can fight, the  girl falls off the roof to her death.

A new horror movie within the last 5 years. The end has a man go through the gate and find himself in an alternate universe with cthulhu like beings out of an hp lovecraft story hovering about.