Just downloaded the game and played it for a few minutes and it's really nicely done and fun to play! I played it on an emulated A500 and was happy to see it running very smoothly despite the fact that you tested it on a much more powerful machine.
Sure it's not action packed but that's clearly the style of this era. I haven't played the original so I can't really judge the quality of the conversion but it definitely gives this 80s NES vibe!
Returning to my web browser after playing it for a few minutes I found myself analyzing everything on the screen as if it was a block of ice I had to push or melt away.
It is a really nice effort, I hope you will continue!
(And why not go for an official license next time? If they accept, the rights owner will likely not ask for an enormous price (if they ask anything) given the target market and you might be able to make it. I would pay 5$ without hesitation for a nicely converted official game.)