Invincibility
Press V to become invincible to enemy fire or damage. Note: This cannot be enabled in campaign mode.
Edit mission scripts
The default mission scripts can be declassified. Enter the mission editor and try to access the pull-down menu. Leave the password prompt blank to declassify a mission. Once this is done, it may be edited to allow invincibility (under the "Skills" setting), hard landings, recovery, and more.