All Fun and Games (not rated)
AGBO; Bloody Disgusting; Dread Central; IMDb; Rotten Tomatoes; Wikipedia
streaming sites: Amazon; Google Play; Hulu; Vudu; YouTube

A kid named Jonah "Jo" Fletcher, who lives in Salem, Massachusetts, is out riding bikes one day with his older brother, Marcus, when they come across a decrepit old house. They go inside to look around, and Jo finds a very old knife hidden in a stove. He takes it home, against his brother's wishes, and soon his mind is corrupted by it. He forces Marcus, their sister Billie (Natalia Dyer, whom I knew from Stranger Things), Billie's friend Sophie, and Billie's boyfriend Pete, to play a game with him. It's just reciting the words that are inscribed on the blade. Marcus is the last one to do so, and the possession that had taken over Jo passes on to him. Before it takes too strong a hold, Billie, Sophie, and Pete go to hang out with some other friends. Subsequently, Marcus kills his uncle Bob, then goes to find the others who had left, and starts killing them one by one. Billie had briefly left the party, and Jo finds her and tells her that Marcus had killed Bob. She doesn't believe him at first, but soon learns what's going on with her friends. So they have to try to find a way to stop Marcus, but don't want to hurt him, because he's not in control of his actions. He ends up stalking them and forcing them to play games like hide & seek, tag, and red Rover.

I don't want to say how it all ends, but the beginning of the movie kind of spoiled the end. It's not a terrible movie, but I wouldn't quite say I liked it.