Is it possible to be able to import script and sprites when playing a game.
If so what script would you use because I'm planing on making a fully moddable
game e.g. Changing strength values and faces.
You can't import scripts in the sense that they can be executed by the game like regular scripts, but you can read text files (and save them back). Look up the File functions in the manual.
DynamicSprite.CreateFromFile allows you to use external sprites in the game.