The title says it all. Mines, flagging, empty cells revealing adjacent non-mine cells, etc..
loadfile("gms.lua")(posx, posy, width in cells, height in cells, difficulty)
Difficulty varies between 0 and 20, with 0% and 100% of the cells being mines, respectively.
Width and height are in cells. Each cell is a 12x12 square. Maximum width and height around 45x25.