¿Como modificar un juego que funcione con Shockwave y NPAPI para que funcione en HTML5 actualmente?

[Moderator moved from Dreamweaver to Animate]

In case you missed the announcements,  both Shockwave and Flash are End of Life.  No future development of such apps is possible. 

• https://helpx.adobe.com/shockwave/shockwave-end-of-life-faq.html
• https://www.adobe.com/products/flashplayer/end-of-life.html

If you believe there is interest & profit potential in an old game, you'll need to create all new programming for it with modern technologies  -- i.e. HTML5, JavaScript, CSS, WebGL, SVG, etc...

Have a look at Adobe Animate

https://www.adobe.com/products/animate.html

to complete what @BenPleysier said, I suppose that your game was last developped by Director.

So, if that is the case,  to run Director, you will need to first install a virtual machine running itself XP or Vista,

It use to run correctly here at the studio, but unfortunnaly, I had a first drive trouble a couple of week ago, and currently, I'm running a SSD disk for booting the system. I haven't right now under hand anything else than Linux on VM...

If you think that my comment could help you in anyway (Director), please don't hesitate and let us know

I am sorry, but this is not a Dreamweaver question. I suggest that you get in touch with the people/organisations/programs involved.