Press [Alt] + [Shift] + V during a mission, display the items screen, then
select and use the "Viewmaster". The screen will flash blue to confirm
correct code entry. The timer will reset to 9:59 and your ranger will be
invincible.
Training mission:
Press T when a mission begins to play without the timer.
Mission select:
Move the savedata.txt file out of the "specops" directory. Restore this
file to return to normal play.