Your problem seems to be related to dimension settings. On the edit game page, if you change the 'Viewport dimensions' to match those of your game, it should work. The issue with my game seemed to be caused by adding a <div> above the <canvas> element. (my code)
I mean, I have the same problem with your game, not with mine: I cannot play because of a black line on top exactly as on the image of digdugdiggy above.
