This is a quick project built with Node.js. It uses the public API at hlkz.sourceruns.org, and my fork of the project hlviewer.js which lets you view Half-Life maps and demos in the browser. I modified it to support the replay format used on the multiplayer KZ/bunnyhop servers, and add a keys-pressed display. You can see the full set of changes here.

Check it out using the demo link above or click repo see the code on GitHub.