Cheats:

 So far, there are no cheat codes, but there are some command-line
 switches.

 These are all the possible switches:

 /SKIP simply puts you right into a level with going thru any other
       screens.
 /LEV is the switch that goes to any level (but with the default
      weapon and health as if starting a new game in level 1).
      The syntax is: LR /LEV LEVELS\MISSxx
      where xx is the level number.
 Apparently what this does is replace level 1 with the given level.
 This means that starting a new game will give the mission briefing
 for level 1 and show the "Loading Level 1" screen. Saving
 and loading saved games works just fine, but if the game is exited
 and restarted, the same command line must be used to restore a saved
 game.
 The level numbers and the MISSxx files don't exactly match up.
 Here's the table:
 Level  1 = levels\miss01
 Level  2 = levels\miss07
 Level  3 = levels\miss04
 Level  4 = levels\miss05
 Level  5 = levels\miss06
 Level  6 = levels\miss08
 Level  7 = levels\miss09
 Level  8 = levels\miss10
 Level  9 = levels\miss11
 Level 10 = levels\miss12
 Level 11 = levels\miss13