From a marketing perspective, you should absolutely have some sort of landing page that explains what I just clicked on before telling me to "wait" because the "application" is loading.
This reminds me of a first date I went on once. We met at Carls Jr because she happened to be passing through the area and didn't have much time, and after 20 mins says, "So, is this heading towards marriage? I don't have time to waste."
Unable to even see this, on iOS it’s just stuck waiting for a service worker to “install.” Why? I wanted a landing page, not just to go straight to the app. If I recall correctly there’s no service workers on iOS yet?
Worked great for me on iOS 11.3.1 in Safari. There’s a two-pane markdown editor along with a feature checklist. The cool thing appears to be that the “app” is being git-clone’d right in your browser’s service worker, which is quite cool if it really is bootstrapping out of a Github repo or something.