This is really beat-up and grainy, but I think it's cool that such a thing exists.
I was unaware of how briefly Mustaine and Burton played together. I got the idea from Metallica documentaries that their days playing San Francisco and the reputation developed in that town were what earned them a recording deal.
Now I realize that Metallica played only a handful of shows in SF before recording Kill 'em All, and that Burton joined in December of '82, and didn't start playing 'til March of '83. Mustaine was already fired by the beginning of April that year, and then Kill 'em All was recorded. What a perilously short window. That means most of the music on Kill 'em All was likely written before Burton joined the band.
http://www.metallicaworld.co.uk/timeline.htm
Some of this footage appeared on Cliff 'em All (and is thus better preserved), but most did not. Without further ado...
Motorbreath
Hit the Lights
Am I Evil?
Anesthesia
Seek and Destroy
Phantom Lord
Whiplash
Mechanix
Jump in the Fire