Most of the noise you hear in the video sounds like it's coming from below the intake manifold. Could the balancer shaft be broken? My biggest concern is, that at mid rpm's there is a secondary noise from below. I guess I need to check compression again.

 

Doubtful, but anything is possible. The balance shaft may be hitting on some out of place valvetrain piece. Start by pulling the valve covers and stop guessing. Carnage can also continue deeper into the engine, but that's how you need to start. If you find a pushrod out of place, then pull the intake off for full inspection (either that or wait until Spring). Sorry!