Hello there; you should definitely put explanations as to how to launch the game, in the game page and maybe in the comments here!
I will put the instructions now:

INSTRUCTIONS TO LAUNCH THE GAME:

1. Go to Scratch’s editor online:
   https://scratch.mit.edu/projects/editor/
   
2. Click ‘File’, then import the .sb3 file from your computer;
3. Now, the game should be running into the right-hand frame.