First i'd like to say: "Welcome to the forum."
And thumbs up for comming up with the idea to create a game of marbles with GE.
However, when you post a game here you either:
1) Post the .ged file, along with the data folder. Usually you put it all in a zip file.
Without the files in the data folder, the graphics are not loaded, or the program crashes on loading (... this happend when I tried to open your .ged)
2) Post the .exe files (Window and/or Linux and/or Mac)
Now you posted the .dat files, but to get them loaded I had to create a .exe file that loads the .dat file you posted...
So the good news is that I could view you demo
And it is what you said it is: a game of marbles.
I can't figure out the controls though: do I click on the marbles to get them to move, or do I drag them?
Sometimes I click on one marble, an other one starts to move ...
The graphics are nice. And the sound is totally that of marbles