Over the weekend I had this dream where I was in Fallout 3, roaming the Wasteland. It was the usual burned out remnants of a long ago destroyed society, but at least I wasn't getting attacked by Raiders or Deathclaws. Then doorways to Hell opened and there were demons all over the place. Which as a video game would probably not be all that different from Doom, except I didn't have a BFG 9000. I mean, I liked Ol' Painless from Fallout 3, but a .32 rifle is not necessarily the best instrument for fighting demons that are 25-30 feet tall. To say nothing of the swarms of moderately large - we're talking beagle-sized, as opposed to bear or car-sized, which is why I said "moderately large" - demonic insects that were this shiny black color, except for the parts that were a dull red.
I have a fair number of dreams that turn into gun battles, but this one didn't. It also didn't become one of those dreams where I'm being chased forever and just running over the same place over and over again. I didn't fight anything. I ran for a while, dodging demons as they clawed their way out of the earth. I slipped into an old one-story house through the back door to catch my breath, and watched 3 Super-Mutants as they peered out at the world through boarded up windows while they argued over what to do. You know things are bad when those guys are hiding and talking rather than running at something and trying to beat it to death with a board with nails in it.
Eventually I wound up in some large garage, or transmission facility, and was going to try and figure out the password for a computer so I could send off a radio signal. What that was meant to accomplish, I don't remember. I don't think I was trying to warn anyone so much as get a lift out of there, but I doubt Hell was only breaking through in the remains of the suburbs of Washington D.C. It didn't come to anything, because I noticed something crawling on the ceiling above me, and I was trying to decide whether it had noticed me yet, and whether I should keep trying or get the heck out when the dream ended.
What I found interesting was that the way things played out in the dream generally conformed to what I enjoyed about playing Fallout 3. I didn't get involved in any combat. Instead I spent my time running/sneaking around, seeing how the inhabitants were reacting to this set of events (that mostly involved dying, or hiding while trying to figure out a way to not die). So that was nice.