It's hard to tell what's more irritating about Playback: its insistence of being an amalgam of The Ring, Scream, and a randomly tiresome slasher flick at the same time; its staunch reliance on completely unpleasant and unsavory characters; or the brief presence of Christian Slater, who was once a pretty cool actor and is now a pretty cool actor who appears in some pretty bad movies. Hardly Mr. Slater's worst horror movie, Playback is instead simply too rote, too obvious, too familiar, and too beholden to well-established horror tropes to warrant much consideration.
A bunch of obnoxious teens do some digging into the history of a legendarily evil filmmaker, only to unleash a videotape that (you guessed it) can kill the people who watch it. Fine, lots of half-decent indie horror films borrow ideas (sometimes whole) from earlier films, but Playback often feels like something that was cooked up at the tail end of the old J-Horror renaissance, and still tossed into production anyway. The narrative jumps from obnoxious teens who will soon be killed (thank god) to a bunch of backstory about an evil, otherworldly filmmaker who lives on through a video image that forces people to kill other people ... oh, and there's also an unseemly subplot about a bunch of guys who are trading in homemade porn videos. One of those guys is Christian Slater.
As if that's not enough to keep track of, it turns out that all of this madness is connected to a mass murder that happened nearby a few years earlier, and this only serves to add a dash of I Know What You Did Last Summer to the proceedings, and that's never a good thing. Clearly too plot-heavy for its own good, and frequently clumsy when shifting between the various subplots, Playback does, at the very least, offer a weird conflagration of several disparate horror tropes -- and it has a few savage kills, which is nice because 98% of its characters are, again, hateful jerks across the board.
Spliced together virtually at random, the subplots come together once in a while, but most of Playback seems like it was cobbled together from material gathered by a lot of horror-movie-watching on the part of writer/director Michael Nickles (which is cool) and then mostly made up on the set (which is not). By the time Playback lurches into a third act that boasts at least a little gore / tension / color, you'll have given up on the plot entirely and started focusing on watching idiots get killed. On the bright side, the movie gets less irritating with each passing murder.