Text screen
From DoomWiki.org
In the Doom games and derivatives a text screen is a screen that presents the player with part of the game's story in text form. The text is typed out sequentially, character after character, over a background made from a repeating flat, while music plays. A text screen appears either at the end of an episode (as in Doom), or after a series of levels (as in Doom II). The text screen is followed by a full-screen picture in Doom, while in Doom II it precedes a level except in the last case, where it is followed by the cast sequence.
Doom II has text screens before Levels 7, 12, 21, and at the very end, as well as before both secret levels (which are played after Level 15). Both episodes of Final Doom operate exactly the same way, as they were originally alternate Doom II PWADs. The same music is used for all of these text screens, with the exception of those of TNT: Evilution (which uses an original, four-second track for each text screen,) and was re-used for the twenty-first level of Plutonia. Doom's story text screens were written by Sandy Petersen [1].
Heretic uses a similar setup as Doom, but Hexen displays a full-screen picture instead of patterning a flat. Strife, on the other hand, does not use text screens at all, instead using a system of slide shows with voice overs to narrate the story after certain key events.
