[SWFKit]

Try

Shell.open(path_to_game.exe);

or

var path = Shell.getEnvironmentVariable("path");
var newpath = path + ";" + path_to_game.exe;
Shell.setEnvironmentVariable("path", newpath);
Shell.run("game.exe");
//The "game.exe" process uses the environment of the calling process
//restore the environment 
Shell.setEnvironmentVariable("path", path);