html 5 version of course buggy while Flash version works fine

Hi E-Learning Heroes Community,

I am having trouble with the html 5 output of my course (created in and published from Storyline 2). Users of the course get stuck at various points and there are some buggy things (e.g. the volume slider getting stuck during audio playback), but mainly the issue is users getting stuck at a few points in particular (a simple forward button on the 'Getting around' slide, and a drag and drop interaction called 'The Money Game') – but only when running the html 5 version of the course! (The Flash version works just fine, and as a temporary workaround I have published the course in Flash only.) This is obviously a problem going forward, however, as browsers phase out (or have already phased out) Flash support. There is also the issue of fuzzy images and text, but as I understand this has been an issue for others as well?

I have uploaded here the output of the course. I'd appreciate any ideas on what the problem could be, or if others have experienced similar discrepancies between Flash/html 5 output in their courses. I have also uploaded the working file if any intrepid souls would like to help me problem-solve. 

Many thanks in advance.

Gareth