All you need to develop the platformer game are
Use your favorite text editor that can edit HTML files. DO NOT USE a word processor. A word processor inserts formatting that makes coding more difficult.
jsgame0.js uses standard HTML5 to load assets through a HTML5 boilerplate. As a result, the page should work even if you just open the file in your browser with the “file://” protocol. For nitpickers, we are making a graphical game so the browser needs to be a graphical one. Something like the text-based browser Lynx would not work.
The code relies on JavaScript so you should make sure JavaScript IS NOT DISABLED in your browser.