Select any level:

 Use a text editor to edit the "freedom.cfg" file in the game folder. Add the
 line "showmissions true" as the last entry in the file. Select the "Load Game"
 option to access any level in the game.

 Regular cheats:

 Use a text editor to edit the "action.cfg" file in the game folder. Add the
 line "bind tilde console" at the top of the file. Then while playing a game,
 press [~] and enter one of the following codes at the console screen to
 activate the corresponding cheat function:

 toggleai                  Enemy AI On/Off
 toggledoors               All Doors Unlocked
 toggledamage              Toggle Damage for All Characters
 badguysarelousyshots.01   Enemies are Less Accurate
 toggledetection           Enemies Cannot Detect You
 gimme [item]              Gives an item, where [item] might be:
                           allergen grenades
                           catteni blaster
                           catteni blaster ammo
                           catteni pistol
                           catteni pistol ammo
                           rifle
                           rifle ammo
                           toolkit