Show HN: Duolingo like app for programming

Looks nice and I like the concepts couple of on-boarding notes on IOS:

- Sign up wasn't super clear that I had successfully registered and I needed to login after I had entered my registration credentials.

- Loading progress (loading awesomeness) took a long while forced a restart in the end

- Enrolling on a course requires content to load but the content itself looks out of place compared to the rest of the look and feel

- Content selection looks great but would it be better to offer a subset based on a bit of an on-boarding walk through?