You explain why a web game should not be big. Slow internet, low ram etc, Yeah. But file counter has not much bearing on this, quite to the contrary. Breaking it down into small chunks makes it more viable for weak clients. So in case of a book "game", you only need to have 1 book page in memory and transmit it over slow internet at a time.
The file counter limit inside a zip for html5 games is arbitrary. It was 500, years ago. Now is 1000. Why there is a limit I do not know. Or how this is handled. If the files are served separatly on demand, this is a server constraint, not a weak client contraint. If the whole project is served upfront, the number of files inside the zip should not be an issue, only the size of the project. Unless of course, the whole project is served upfront in all its tiny fragments, which would be the worst of both worlds.