Presumably in Darkplaces when the map loads (or player enters a new area, like starting a new episode or map pack) you could write a file called introscreen.cfg, which would look something like this:
set g_intro 1
map <relevant intro map's name>
autoexec.cfg would have "exec introscreen.cfg" in it so that when Quake starts, it opens the map. Because g_intro is set, the game knows to find an intermission point to place the camera and just watch as monsters mule about etc.
Each episode or related group of levels would have its own intro map. For this example, I'll assume there's 4 intro screens, one for each episode (defaulting to episode 1). Each map would have an intermission camera entity and a bunch of monsters to watch. You could even allow monster & fake player spawners off screen to generate mock battles for his viewing pleasure.
Using the a similar menu system to what Nexuiz uses (but without the background so the player can better see the stuff behind), you could let the player set up his game. Any options screen would have a background for readablility, but otherwise it's mostly open looking.
When the intro map loads, g_intro is set to 0 so that when he starts a new game, he gets to actually play.
I imagine that this could very easily be done. ^_^ If I ever get back to working on Conquest, I'd like to do this.
