When you reach Phobos Labs Level 2, the BFG-9000 that's shown on the "Martian Buddy Blaster" arcade machine is the BFG from the original "Doom" games.
Master Sergeant Kelly who plays a main role in "Doom 3", has a cameo in this game where you find a picture of him in Erebus Level 3 on a wall, just as you grab the double-barrel shotgun.
On the BFG Edition, the roles of Screaming Marines/Infected Carriers are portrayed by Ice Cube (uncredited).