A cute gambling game. :) Very satisfying.
If you roll again, you stand to win 20/6 + 30/6 + 40/6 + 50/6 + 60/6 = 200/6 points. If you get [·] one, you lose everything you earned plus 15 and that is 1/6 chance. So in essence it is a sound choice to keep betting until you make 185+ points. After that it is a poor choice to roll again.