The differences between the iOS app and the web page were startling about a year ago when I first started using it. In particular how different the iOS's coach was and the "on-track" concept on the web. I was excited that they wanted to make it more similar, but then they just cut the coach which I had vastly preferred.
For the first German lesson, these are on capitalising nouns, grammatical gender, umlauts and verb conjugation.
I wish they'd add it to the app!