Mid Boss
I'm just curious how the gameshark works. Mainly, can it work with previously saved games? Can you then 'turn off' the gameshark once you're through with it and return to the said saved game? Or is there a memory card you HAVE to save onto for it to work?

Any all info would be great.
Gameshark works by altering memory contents. The "codes" are memory addresses and the replacement contents (though there are some types that have special functions so that e.g. a range of values can be altered without entering many codes).

The "dongle" that comes with the Gameshark is for its own use in storing codes; it also doubles as a form of copy protection for the Gameshark. It has nothing to do with game saves. If you have a saved game that you want to improve, you can load up the GS, activate the codes to hardwire whatever stats/items/etc. you want, load your game and save it again. Since that saves the altered values to your VMU/memcard, you can now load it up again without the GS and have those same stats/items/whatever.