One of the central problems that comes from making a film like this is that many of the characters end up being very unsympathetic. This leaves it to the actors to create, if not likeable characters, at least interesting ones. Emile Hirsch does solid work as arrogant group ringleader Johnny Truelove. Some may question his weak presence, and point out that he's not demanding enough for the role. But really, that's the whole point. He's a phony - just a kid with a lot of money that likes playing the tough guy.
Meanwhile, drug-upped Jake Mazursky (played fantastically by Ben Foster, who always makes for an awesome over-the-top psycho) really is a tough guy. When Truelove snatches his brother, Mazursky makes it his life's purpose to hunt the dirtbag down and make him suffer. With such great build-up, it's too bad nothing ever comes of this. After the movie's climax, the character simply vanishes from the film. Very annoying.
The most well rounded character in the bunch is played by - surprise, surprise - Justin Timberlake. The bond his character forms with the kidnapped kid (Anton Yelchin, also great) is handled flawlessly, and it's their chemistry that makes the impact of the ending so powerfully emotional. I especially appreciated how director Nick Cassavetes didn't overdo the scene, as it made the horrible event feel all the more brutal and real.
Some of the other directing choices, however, turn out to be a little off-putting. The awkward opening credits are an example of this, as are the very forced faux interviews (especially the cringe-inducing one with Sharon Stone in that fat suit - yikes!). On top of this, there are a few ridiculous sequences that take away from the harshly realistic nature of the film (the incredibly random fight sequence in particular - cool, but so pointless), but the overall strength of the story remains intact. As long as you can ignore its faults, ALPHA DOG makes for an interesting film, and certainly a worthwhile cautionary tale.
A Cautionary Tale: The Making of Alpha Dog (11:28): A worthless featurette including interviews of the cast/crew discussing how powerful ALPHA DOG's story is, while contributing nothing else of interest.
Witness Timeline: A mildly cool feature that allows you to view various quotes from the real life witness counterparts. It also gives you easy access to the scenes in the film involving the witnesses.