The minigames are called with a singe fieldscript function, with arguments, but they themselves have access to the savemap. The "Big Four" minigames, Bike, Jet (rollor coaster), snowboard, and Chocobo race use the same engine. (I call it "track" for lack of a better word) The Condor one is by itself, and also the sub game if I remeber
The other minigames in golden saucer are all written in fieldscript.