I really want to sign up and share a creation, but when I do either sign up or sign in, it gives me a firebase url that just redirects me to the app store. I can't find any way to sign up.

I'll click "Sign in to Downpour", it will bring me to a "Open link in App?" page, I press "Open", and then it brings me to a "Downpour -- make a game" page and I click open again which brings me to the app store. The app is installed on my phone.