Eminem is back on the scene after an absence equaling a lifetime in rap years.

His opening shot from his upcoming CD “Relapse” is “Crack a Bottle,” which has just leaked online, again (other versions leaked previously).

My first response — is that all there is? The track, featuring both Dr. Dre and 50 Cent, is listenable enough but average at best. It sounds like something Eminem, or Dr. Dre or 50 Cent for that matter, could’ve done before.