Cheats:

 Type VIPER on the logon screen to access all the missions. While in a
 mission press:

 [[Alt]][I]  Invulnerable AHX-1
 [[Alt]][L]  Reload weapons
 [[Alt]][R]  Fix damage
 [[Alt]][A]  Show all targets on radar
 [[Alt]][X]  Crash Viper
 [[Alt]][Q]  Change flight model real/arcade
 [[Alt]][K]  Stop smoke trails
 [[Alt]][J]  Display the render rate (FPS)