Thanks for the quick reply and update. The only issue I had was I can't have the game in full view as my browser will overlap the edges, even in full screen, and I did have a couple of freezes, again, most likely down to my using the Brave browser. The nostalgia factor was the main attraction for me and I had to mention the gun, as it used to bother me back when I played it in the early 90s that bullets just appeared from the main character.
I'll certainly keep a look out for if/when you make a Unity engine version. Thanks again, Rick.