From early 1993 to late 1995, Apogee and 3D Realms released slide shows of
their upcoming games which featured roughly a dozen screen shots from the
game in question.  Since then, these sneak preview images have moved to
Apogee's web site, obsoleting the need for slide show archive bundles.
However, most of these packages are still available at Apogee's FTP site
at ftp://ftp.3drealms.com/misc/oldshots/.

      
From Apogee:

   Game                           Date Released
   ----                           -------------
   Boppin                           10/18/94  *
   Rise of the Triad #2             10/11/94
   Wacky Wheels                     08/30/94  *
   XenoPhage: Alien Bloodsport      08/15/94  *^
   Rise of the Triad #1             07/15/94  *
   Mystic Towers                    07/01/94  *
   Hocus Pocus                      05/16/94  *
   Blake Stone: Aliens of Gold #3   02/11/94
   Raptor: Call of the Shadows      01/27/94  *
   Duke Nukem II                    11/18/93  *
   Halloween Harry #2               10/06/93
   Halloween Harry #1                08/93    *
   Monster Bash                     06/11/93  *
   Bio Menace                       05/23/93  *
   Blake Stone: Aliens of Gold #1   03/25/93  *

      3D Realms:

   Game                              Date Released
   ----                              -------------
   Duke Nukem 3D                       11/19/95  *
   Duke Nukem 3D and Shadow Warrior    08/11/95
   Terminal Velocity                   04/04/95  *

 * - This indicates the first U.S. release of an official slide show of the
     particular game.

 ^ - This is a self-running executable demo with no independent image files.