I've used Duolingo for almost 4 years now. The website version is fine. The app is not. Stop me if this sounds familiar: you're doing a difficult grammatical lesson (the tips barely scratch the surface, if the exist). This is past checkpoint 7 so it's tough. You fail 5 times, you're out of hearts. You have to "practice". You then get the joy of translating "I am a boy" and "I like apples" 40 times. Hearts and "practice" are so horrifically bad it's a wonder anyone uses this app.