To activate fly mode, go to options, type in the cheatwindow: 'peterpan'. You will have to repeat this every level you start.
To activate all movies, press in the cheat window: 'intelsitrep'.
To unlock god mode or invinsibility, go to options, open the cheat window and press: 'firstlaw'. You will have to repeat this for every new level.
All Single Player Levels
To unlock all levels, press in the cheat window: 'greenlight'.
To have infinite ammo, while in game, go to options and choose cheats. Type in 'madminute'. You will have to repeat this for every game you start.