apparently, someone under alias Stinger uploaded some of his Dirty Bomb Alpha clips:
Amazing things I found:
-You can actually enter the chapel rather than only riding the MG in Chapel
-The barricade in Bridge is actually destroyable with explosive (there's a health bar).
-Any mercs can use whatever weapon (Sky with KEK-10, Bush with Dreiss, etc).
-EV start place is different in Bridge (below the rail train).