Copied from another forum.. really works great 
Find and edit "DevMode.lua" with wordpad or equiv. Add these two lines to the end of the file:
Input:BindCommandToKey("#Game:Save('quicksaved_game');","f9",1);
Input:BindCommandToKey("#Game:Load('quicksaved_game');","f10",1);
Use -DEVMODE on shortcut launch. You can quicksave with F9 and quickload with F10.
P.S. (Put the -DEVMODE after the quotes)
example: ... farcry.exe" -DEVMODE
Find and edit "DevMode.lua" with wordpad or equiv. Add these two lines to the end of the file:
Input:BindCommandToKey("#Game:Save('quicksaved_game');","f9",1);
Input:BindCommandToKey("#Game:Load('quicksaved_game');","f10",1);
Use -DEVMODE on shortcut launch. You can quicksave with F9 and quickload with F10.
P.S. (Put the -DEVMODE after the quotes)
example: ... farcry.exe" -DEVMODE