In modern android phones browsers cannot acces file structure. If you have images inside the folders, browser wont be able to open the links, because browsers have no right to read filenames. Android substitutes filenames with a numbers. Try opening any image with your browser, and you will see that in adress bar there is no file name, only numbers, unlike pc and lunix. To play html game in android you need to run local server, and open game trough 127.0.0.1, so your browser can access your files. Therefore, "mobile game" tag is misleading. Otherwise every html game should have that tag. Here is a difference between opening html with and without local server running.