Director's Cut could mean any number of things...studio interference, re- shoots, poor test screenings. Most of the time that just means a couple more minutes added but sometimes there are drastic differences from the original released. This is one of those big changes. I liked this movie with it's sharp writing and nice mix of violence with dark humor. 'Like' has become 'love'. If you've never seen it and your a big film buff I'd say watch both versions to see the difference. If you've never seen it, Straight Up is hands down the way to go.
Review of Payback: Straight Up
