I'm glad people make movies such as Heaven Knows What, a hard-core immersion into the world of homeless New York City drug addicts. That doesn't mean that the movie, directed by Ben and Joshua Safdie, should be seen by everyone. In fact, Heaven Knows What can become a bit of an endurance test. The Safdies' rough-edged look at wayward, inarticulate characters seems longer on urgency than insight. The film springs from an unpublished memoir by Arielle Holmes, who also stars in the movie as Haley, a young woman torn between two guys. Caleb Landry Jones plays Illya, a young man who opens the movie by encouraging Holmes' character to commit suicide, a pretty good signal that she probably shouldn't be expecting any Valentine's Day cards. Buddy Duress appears as Mike, a drug dealer who's a little less abusive when it comes to Haley. I'm not entirely sure why we need to know what it's like to live on the streets of New York, do drugs and develop self-destructive loyalties, but the raw power and authenticity of many of the movie's scenes can't be denied and the casts' commitment -- particularly that Holmes -- qualifies as nothing short of total.