I appreciate the effort to define a fast subset of HTML, but the AMP loader on google.com makes the whole page-loading experience different and worse in many ways. Several times today while trying to visit different sites, the AMP JS loader has broken down, displaying only the Google address bar, a fake AMP address bar below it with the intended URL, and a multicolored Android-style circle spinning endlessly (on an iPhone). All the native browser controls for page lifecycle (including timeouts and Reload button) were completely ineffective. It's important for the loader to get its replacement for these things right if it's going to try to supplant the browser's built-in functionality, and it currently doesn't succeed at that.