Important: Run the game atleast once before applying this unlocker.
Unpack/overwrite file into your game directory, start "pzunlock.exe"
and you will have access to all missions from the Load Game menu.
/Team PiZZADOX
download the file: unreal_2-unlocker.zip
(to unpack archives use: WinZip,WinAce, WinRar)