Play Any Mission
     In  the  Campaign Menu, right click on the microphone on the left
side  of  the  screen.  Type  'idaho'  and  a  menu will appear on the
top-right of the screen

Invulnerability
     At the Weapons Loadout Menu, type 'I AM THE ACE!!'.

Level select:
     Highlight the microphone on the left side of the main menu in the
campaign.  Press  the right mouse button, then type: idaho. A new drop
down  menu that allows any level to be selected will appear at the top
right of the screen.

All gallery pictures:
     Select  the  "Previous Missions" option at the campaign mode main
menu.  Click the "Rogue Pilots & Co." symbol on the bottom left of the
screen, then type: ispy.