Perimeter
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
All Levels
Create a new directory with "Profile0" name in your "c:\Program Files\Codemasters\Perimeter\Resource\Saves\" directory.
Create a new file with text editor, called as "data" (without extension!) in your "Profile0" directory.
Just copy and paste the following lines into your "data" file:
[General] name=ABBYCHEAT lastMissionNumber=28 difficulty=1
Save your file. Now you have access to all missions in campaign/battle mode.