Press F9 to pause the game. Hold HELP, Left Shift, and 1 
 (main keyboard). Let go of all three, and press F10 to 
 restart the game. 
 From now on the following keys are activated: 
 
 1-5 (main keyboard)-Warp to corresponding level 
 [F1]-[F4]-Warp to section 1-4 in current level 
 
 If you are almost dead, just use the F1-F4 keys