Yes, one of our play testers used MiSTer to complete the game. I believe you need to set "bios: disable" for it to run. Some other games have the same issue.
Alternatively, you can use the newer Mega Drive core which doesn't have the above issue.
Thanks I will give that a try. In the mean time I have been playing it on my Analogue Pocket and it's awesome!! :)
Yes setting the bios to disable works perfectly - thanks again!