Im loving this app, the short lessons are great and the pronunciation voice overs are very helpful. The only problem Ive encountered is sometimes it will speak and sentence and give me a "type what she said" test, and she had spoken a word I had not previously seen spelled out, causing me to get it wrong and lose a health bar. And when you are learning German trying to spell a word you havent seen is difficult at best.
To fix this I would change it to ensure you never have to spell a word you havent seen, or increase the health you have a few bars.
This is a fantastic app in every other regard so far. Thanks to whoever made it
Stigsbie about Duolingo Learn Many Languages for Free, v5.0.14