-dev is the developer it turns on an option that shows everyline exicuted by the game so u can see your scripts being executed and it also shows all code and things during the game in the console and echos it to the top left hand corner
-zone is bit more tricky its a command used to legthen the ammount of lines a script can have in counterstrike/halflife default is 32 lines of code i think, -zone 1024 legthens its to 1024 lines of code before the script will no longer execute.
also ill add this one to the list
-toconsole
if u al do alot of direct connections and script executing this is a good tool loads counterstrike directly into the console window