Unlock all levels:
Make a directory called Profile0 in c:Program FilesCodemastersPerimeterResourceSaves

Now make a txt file with notepad called data. Do not give it a .txt extension. Just call it data with no extension. Put it in the Profile0 folder.

Now copy and paste this into the data file:

[General]
name=ABBYCHEAT
lastMissionNumber=28
difficulty=1

Save the file and run the game. All levels will be unlocked.