I currently do not see Shooter Game being ran on a server for HTML5, like Tappy Chicken is as a demo. If you want to play Shooter Game on HTML5 and it’s currently ready for HTML5, you can simply download it from the Epic Games Launcher, open it within the Editor and package it for HTML5. You’ll need to create a simple http server for it to run through FireFox though.
I will continue to search to see if Shooter Game is set up anywhere. If I find a link, I will come back and post the URL.