So now you got it to work in Greenfoot Version 3.1.0 (you're not the only one). Why does that have anything to do with other users running the scenario?
What do you mean the scenario was broken? You didn't change anything pertaining to this scenario by any other user. It's possible that you're playing around with Java and your browser's settings but nothing was changed.
Why don't you make a score table where it says other players' ranks and scores instead of just my own high score.
You can look at my scores class: http://www.greenfoot.org/scenarios/19309
I'm working on making it normal speed, now it's extremely slow. With my Scores class all the users are displayed with their image, rank, score, and name not just the top few users.
2017/6/22
Advanced Mouse Control
2017/6/22
Advanced Mouse Control
2017/6/22
Advanced Mouse Control
2017/6/22
Speed3D
2017/6/22
Speed3D
2017/6/22
Speed3D
2017/6/22
Speed3D
2017/6/22
Speed3D
2017/6/19
KravchenkoAlina_230_LineGame